Sometimes, it comes down to who's healthy Key injuries could provide matchup advantages in this weekend's games By Chris Wesseling updated 1:50 p.m. Former Packers great Jerry Kramer, author of the best-selling 1967 classic Instant Replay, used to say that Vince Lombardi takes injuries as "personal insults." If football appeals to fans as an island of certainty in a world with ever increasing gray area, that goes double for head coaches. There can be nothing vague about a defensive scheme or an offensive game-plan when implementing a strategy to exploit matchups. Injured players leave too much room for doubt, a condition abhorred by NFL coaches. Key injuries have the potential to tip the field in wild card round of this year's postseason. Let's take a look at the matchups, starting with the injury-riddled. Steelers at Broncos Tweaking his ankle sprain in the regular-season finale, Ben Roethlisberger has run up against one of Kramer's football maxims: "It's hard to have an injury heal when you have the hell beat out of you one day every week." Big Ben is fully expected to play Sunday, but his renowned improvisational skills will be compromised against the Broncos" formidable pass-rushing duo of Elvis Dumervil and defensive rookie of the year favorite Von Miller. On the positive side of the ledger, receiver Emmanuel Sanders (foot, knee) will return to provide Roethlisberger with another run-after-catch threat. Isaac Redman is an upgrade in pass protection and perhaps in short-yardage, but the most significant fallout from Rashard Mendenhall's ACL tear is the lack of big-play ability and depth. Third-down back Mewelde Moore is sidelined with a knee injury of his own, leaving undrafted rookie free agents John Clay and Chad Spann as the backups. Flipping to the other side of the ball, LaMarr Woodley is practicing fully this week and may finally be over a hamstring injury that has nagged the October AFC defensive player of the month since Halloween. Woodley and bookend edge-rusher James Harrison will work to confine Tim Tebow to the pocket in an effort to make up for the loss of free safety Ryan Clark. The rock-solid Clark will be held out after losing his spleen and gall bladder back in 2007 due to the stress of playing in Denver's high-altitude air. The Broncos have injury concerns of their own on defense. After recording 11 sacks and a league-leading 18 QB hits through November, Miller has managed seven tackles and one sack in the past four games while playing through a surgically repaired thumb. He was even benched for ineffectiveness in the regular-season finale. A struggling secondary will be without Brian Dawkins (neck), a defensive leader and veteran of 18 playoff games. Bengals at Texans Both teams are relatively healthy. The one Cincinnati injury of note is A.J. Green's Grade-3 shoulder separation, as the rookie sensation has been held to an average of two catches and 25.5 yards on 8.5 targets in the past two games. Andy Dalton felt fine Thursday after a bout with the 24-hour flu bug. Underrated pass rusher Carlos Dunlap is on track to play after battling a hamstring injury down the stretch. Houston's shutdown corner Johnathan Joseph has been limited in practice with a sore Achilles', potentially evening the matchup with Green. The major injury news is on offense, where the Texans welcome back a healthy Andre Johnson for the first playoff game in his nine-year career. With Leon Hall (torn Achilles') out for the season, the Bengals don't have a corner capable of hanging with Gary Kubiak's best player. This is a different offense with Johnson on the field, providing rookie T.J. Yates a dangerous vertical weapon while opening running lanes for Arian Foster and Ben Tate. Lions at Saints Hard-luck feature back Kevin Smith reported no more than general soreness after a nasty collision with Tony Scheffler in Wednesday's practice. Detroit's offense will be at full strength while the secondary welcomes back its defensive "soul" in free safety Louis Delmas, who missed the final six regular-season contests with a knee injury. The Lions secondary needs all the reinforcements it can muster after surrendering 332 passing yards per game in Delmas" absence. Even with Lance Moore's hamstring injury and Mark Ingram's season-ending turf toe surgery, the Saints can rest easily in the comfort of their deep roster. Although Moore has joined Pro Bowl picks Calvin Johnson, Greg Jennings, Larry Fitzgerald, Roddy White and Andre Johnson as one of just six NFL receivers with at least eight touchdowns in three of the past four seasons, coach Sean Payton can paper over his absence by expanding the roles of big-play threats Robert Meachem and Devery Henderson. New Orleans well-rounded ground attack hasn't missed a beat with hard-charging Chris Ivory stepping in for Ingram between the tackles. Falcons at Giants The Giants" training room has seen an ongoing parade of players over the past month, but key offensive weapons Ahmad Bradshaw (foot), Hakeem Nicks (hamstring) and Mario Manningham (knee) appear to have turned a corner in their injuries. Disruptive pass rushers Justin Tuck (neck, groin, toe) and Osi Umenyiora (ankle, knee) are both expected to be available on Sunday, leaving tight end Jake Ballard (knee) as the one question mark. The major question marks for Atlanta are on defense, where strong-side linebacker Stephen Nicholas" lingering knee injury has contributed to a declining run defense over the last month. The good news is that Brent Grimes, one of the league's premier cover corners, returns from a knee injury to give the secondary a semblance of a prayer against Nicks and hot playmaker Victor Cruz. A healthy Falcons offensive is as dangerous as it has been since Matt Ryan entered the league four years ago, thanks to the explosive Julio Jones and an efficient no-huddle attack.