HOUSTON -- Texans defensive end J.J. Watt is out for the season after he suffered a tibial plateau fracture in the team's 42-34 loss to the Kansas City Chiefs, coach Bill O'Brien said Monday. 
 
 Watt fell to the ground while engaged in a block on the Chiefs' opening drive. The veteran defensive end was helped to the sideline by the Texans training staff and was looked at in the sideline tent before being taken off on a cart. He was eventually taken to a hospital in an ambulance. 
 
 O'Brien also confirmed that outside linebacker Whitney Mercilus will be out for the remainder of the season with a torn pectoral muscle. 
 
 "The deal in this league is that the train doesn't stop moving," O'Brien said. "These guys are there, and they're going to have to step in. 
 
 "It's going to be multiple guys. You don't replace J.J. Watt or Whitney Mercilus with one guy. That's ridiculous. So it's going to a lot of different guys that are going to chip in to help." 
 
 On Monday morning, Watt tweeted to apologize to his teammates and the city of Houston. 
 
 I can't sugarcoat it, I am devastated. 
 
 All I want to do is be out there on that field for my teammates and this city. 
 
 I'm sorry. — JJ Watt (@JJWatt) October 9, 2017 
 
 Watt, 28, missed the last 13 games of the 2016 regular season because of a back injury. He played in his first regular-season game since his September 2016 back surgery in this season's opener against the Jacksonville Jaguars. In four games, Watt had 13 tackles, but he did not have a sack. ||||| Bob Levey/Getty Images 
 
 Houston Texans superstar defensive lineman J.J. Watt suffered a serious left leg injury Sunday against the Kansas City Chiefs in the first quarter and was unable to walk off the field under his own power. 
 
 The Texans announced Watt has a tibial plateau fracture, and head coach Bill O'Brien confirmed Monday that Watt will miss the season after Ian Rapoport of NFL Network reported the news Sunday night. 
 
 Watt was seen on crutches entering an ambulance after suffering the injury, per Aaron Wilson of the Houston Chronicle. 
 
 Watt and his brother T.J. tweeted about the injury: 
 
 Adding to the Texans' woes in Week 5, John McClain of the Houston Chronicle reported Whitney Mercilus needs surgery to repair a torn pectoral muscle suffered in the first quarter and will miss the rest of the season. 
 
 Injuries are becoming a worrying storyline for Watt. A back injury cost him all but three games in the 2016 season, and he dislocated a finger in the season opener, though he didn't miss a game. He also dealt with a broken hand in 2015. 
 
 When he's stayed healthy, he's been the most dominant defensive player in the NFL. In his first five seasons (2011-15), he registered 372 tackles, 74.5 sacks, 15 forced fumbles, 12 fumble recoveries and 45 pass deflections. 
 
 Pro Football Focus ranked him as its top player for the 2014 season and No. 5 player in 2015. He's a three-time Associated Press Defensive Player of the Year, four-time Pro Bowler and four-time first-team All-Pro selection. 
 
 Watt is the heartbeat of the Texans defense and recently used his platform to raise over $37 million in donations for relief for those affected by Hurricane Harvey as more than 200,000 people donated. 
 
 While the team managed to reach the postseason without Watt in 2016, the defense is far better when he's in the lineup alongside Jadeveon Clowney. 
 
 In his absence, Brandon Dunn, Joel Heath and Carlos Watkins should see more time in Houston's defensive line rotation. ||||| Photo: Karen Warren, Staff Photographer Image 1 of / 4 Caption Close Image 1 of 4 Texans defensive end J.J. Watt even beat the city's team owners in creating a fundraiser to aid in Houston's recovery efforts. The fund is up to $4,900,000. Texans defensive end J.J. Watt even beat the city's team owners in creating a fundraiser to aid in Houston's recovery efforts. The fund is up to $4,900,000. Photo: Karen Warren, Staff Photographer Image 2 of 4 Houston Texans defensive end J.J. Watt waves to the fans as he walks to practice during training camp at The Methodist Training Center on Monday, Aug. 21, 2017, in Houston. ( Brett Coomer / Houston Chronicle ) Houston Texans defensive end J.J. Watt waves to the fans as he walks to practice during training camp at The Methodist Training Center on Monday, Aug. 21, 2017, in Houston. ( Brett Coomer / Houston Chronicle ) Photo: Brett Coomer, Staff Image 3 of 4 Long a fan favorite, three-time NFL Defensive Player of the Year J.J. Watt, right, has continually been forced to raise his fundraising goal upward as people respond to his call for help. Long a fan favorite, three-time NFL Defensive Player of the Year J.J. Watt, right, has continually been forced to raise his fundraising goal upward as people respond to his call for help. Photo: Brett Coomer, Staff Image 4 of 4 Houston Chronicle columnist Brian Smith Wednesday, March 30, 2016. ( Karen Warren / Houston Chronicle ) Houston Chronicle columnist Brian Smith Wednesday, March 30, 2016. ( Karen Warren / Houston Chronicle ) Photo: Karen Warren, Staff J.J. Watt and his followers have your back, Houston 1 / 4 Back to Gallery 
 
 He has been a beacon during the devastation and chaos. 
 
 I'm not saying J.J. Watt has been a hero. That is a revered word reserved for the mostly anonymous, who have risked their lives over and over to save and preserve others, ever since Harvey wrecked Houston. 
 
 But true colors and real people shine through during times like this. And we've seen the best of this city's most famous athlete since a Category 4 hurricane became the flood that won't end. 
 
 A week ago, Watt was with the Texans in New Orleans, playfully asking his 3.9 million Twitter followers where the best place was for a beignet. He took a ride around the city. He played one series in a pointless preseason game against the Saints. 
 
 Then Friday, there was just this: "Stay safe Houston. We're thinking about you." 
 
 Translator To read this article in one of Houston's most-spoken languages, click on the button below. Brian T. Smith 
 
 Two days after that - on Sunday, when Harvey's local destruction was becoming a numbing reality - Watt posted the first of the personal videos that haven't ended. 
 
 He didn't wait for anyone else to speak up first. He beat Bob McNair, Leslie Alexander, Jim Crane and so many others to the podium. Watt composed an honest message, reached out to all those who follow him and shined a spotlight on Houston's unthinkable struggles. 
 
 "That's our city. It's very tough to watch your city get hit by such a bad storm and not be there to help. … So what I do want to do is, I want to start a fundraiser, because I know that these recovery efforts are going to be massive," Watt said. "There's going to be a whole bunch of people that we need to help get back on their feet and there's going to be a lot we need to do to help rebuild." 
 
 His goal was $200,000. 
 
 Watt brought it halfway himself, donating $100,000 to the Houston Flood Relief Fund for Hurricane Harvey victims at YouCaring.com/JJWatt. 
 
 The same day that No. 99 posted his first video - staring into a lens; simple and direct with no fancy production tricks - he was forced to add this: "Hey @youcaring I think we may have broken the website. Can you please help so that we can raise as much money as possible for these folks???" 
 
 And this: "The initial 200k was raised in less than 2 hours. I have now raised the goal to 500k. Your support is phenomenal!" 
 
 New Rockets guard Chris Paul soon kicked in $50,000, which allowed Watt to reach his second goal within 24 hours. 
 
 The videos just kept coming. As did a CNN appearance to promote the fund and raise more donations for Harvey victims. 
 
 "$1 MILLION! New Goal: $1.5 Million," Watt tweeted. 
 
 "$2 MILLION! New Goal: $3 Million," just 16 hours later. 
 
 As I type this, the current total is more than $4,900,000 which has been raised by 48,565 donors in only two-plus days. 
 
 Remember when hating on the three-time NFL Defensive Player of the Year was so hip and cool? 
 
 Too many commercials. Too much endless attention. Total overexposure. 
 
 Uhhh, hey J.J. … Houston will never forget this. 
 
 "It's been an unbelievable display of what can happen when people come together. … That's what Houston's all about," Watt said. "It's a very diverse city. It's a very resilient city. It's been through things like this before - maybe not of this magnitude, but it's been through these types of situations. People are coming together, people are helping raise each other up." 
 
 Bill O'Brien gave a shoutout to Watt's efforts while the Texans adjusted to their temporary home in Frisco. The team's coach then issued his strongest statement since he became a Houstonian, again proving that he runs much deeper than his tough exterior. 
 
 "We're going to dedicate this season to the city of Houston, the people of Houston," an emotional O'Brien said. "There are no guarantees in football. … But I will guarantee that this team will go out every Sunday, Monday, Thursday - whenever they ask us to play - and we'll play our (butts) off for the city of Houston. I promise you that." 
 
 Since Watt started his fund, McNair's Texans pledged $1 million to the United Way, which was matched by the NFL Foundation. Crane's Astros have promised $4 million that will go toward Harvey relief efforts. 
 
 Alexander one-upped them all, increasing his initial $4 million pledge to $10 million Tuesday. 
 
 The same day, Tennessee Titans owner Amy Adams Strunk donated $1 million to the fund that Watt started with one short video. 
 
 "Humanity is incredible. The positive vibes are unbelievable," Watt said. "Houston, we're all thinking of you. The whole world is wishing you the best. Stay strong. We've all got your back." 
 
 The money will obviously have to be followed. But Watt long ago proved his foundation's worth when it comes to charity, and he has touched the lives of everyone from firefighters and teachers to young athletes and sick children. 
 
 "I'm working very hard … to make sure this money goes directly to the people, not to administrative fees or anything like that," Watt said. 
 
 To the people. 
 
 On the playing field, Watt's at his best surrounded by adoring thousands. Because of Harvey, many who love him are now just trying to hold on and survive. 
 
 During some of the darkest days in this city's history, it has been impossible to doubt the power and sincerity of No. 99. ||||| HOUSTON (AP) — Houston Texans star J.J. Watt said Monday that he has distributed the $41.6 million his foundation raised to help rebuild the Texas Gulf Coast after Hurricane Harvey. 
 
 An online fundraiser Watt launched after the storm hit Texas last year went viral and far exceeded his original goal of raising $200,000. 
 
 "It's incredible to see just the generosity of strangers and what it's able to do and what it's able to accomplish, and the fact that that's just year one," Watt said. "We still have more to do and we still have a lot going on moving forward." 
 
 Watt routed the money to eight groups actively involved in Texas' rebuilding and recovery. According to the Texans, the funds have already been used to clean up and rebuild more than 600 homes, distribute more than 26 million meals and provide health care to more than 6,500 people. 
 
 The three-time NFL Defensive Player of the Year has dealt with serious injuries in each of the last two seasons, playing just eight games combined in 2016-17, though he's back and healthy now. He said working on this project and seeing how people came together to help others in such a huge time of need was good for him. 
 
 "As you look back on it, you really understand how incredible it really was and how thankful that I am for so many people to help out and to be willing to help out," Watt said. "I was going through some tough times myself the last two years, so I think that it really helped show me the good side of people and that I should have hope and ... have positivity." 
 
 Houston coach Bill O'Brien said he spoke to the team Monday about the impact Watt's fundraiser had on the community, and he raved about his superstar defensive end. 
 
 "I don't even know if words can describe that, what he's meant to the city of Houston, everything that he's done," O'Brien said. "He was hands-on with it. He's been hands-on with how to distribute the money, where it goes, all those things. We have a great deal of respect for what he's done, and I know the city does, too." 
 
 Watt, who is entering his eighth NFL season, talked about how moved he was that everyone from celebrities to children with lemonade stands helped raise funds to help the victims of the storm, which made landfall last Aug. 25 and left torrential flooding in its wake. He said he felt a lot of pressure to make sure the money was used to make the biggest impact in areas where it was needed most. 
 
 "Obviously, I wasn't planning on being in such a wild situation from the start, but I had an incredible support team around me and I had tons of people help me out," he said. "We did loads and loads of research and we spent hours and hours doing the phone calls and the meetings and talking with everybody and gathering as much information as we could, so we could do it the right way." 
 
 "Because that's the only thing that we wanted out of all of it — we wanted to do it the right way and make sure that we did proud to people who trusted us," Watt said. 
 
 ___ 
 
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– Houston Texans fans who have been holding their breath since their superstar defensive end JJ Watt went down with an injury in the first quarter of the team's 42-34 loss to the Kansas City Chiefs Sunday had their collective hearts broken on Monday, per Bleacher Report. After the Texans tweeted Sunday evening that Watt, a three-time NFL Defensive Player of the Year, had suffered a tibial plateau fracture in his left leg, head coach Bill O'Brien confirmed that the injury had ended Watt's season. Early Monday morning Watt tweeted, "I can't sugarcoat it, I am devastated. All I want to do is be out there on that field for my teammates and this city. I'm sorry." Watt's injury occurred at the seven-minute mark of the first quarter. While attempting to work his way around the Chiefs' offensive line he appeared to have his leg run into by his own teammate, causing him to fall to the ground. Watt was escorted to the sideline by Texans staff and eventually put into an ambulance and taken to a hospital, ESPN reports. Making matters worse for the Texans, Watts' teammate Whitney Mercilus was also forced to leave Sunday's game with a season-ending injury. Watt, 28, sat out most of last season with a back injury.