Richards made his NHL debut with the Flyers the following season, 2005–06, and scored a goal in his first game on October 5, 2005, against the New York Rangers.
Later in the season, he scored his first career NHL hat-trick, which included two short-handed goals, against the New York Islanders on February 8, 2006.
His hat-trick was the first by a Flyer rookie since Mikael Renberg on February 15, 1994.
 Richards finished his NHL rookie season with 34 points in 79 games, third among Flyers rookies, behind Jeff Carter (drafted the same year as Richards, 11th overall) and R. J. Umberger, respectively.

Following an injury-shortened sophomore season – Richards was kept to 32 points in 59 games due to stomach surgery – Richards emerged as a star with the Flyers in 2007–08 and topped the team in scoring with 75 points.
Recognizing his ascent as a leader on the team, Richards was named one of the Flyers' alternate captains at the outset of the season and was signed to a lengthy 12-year contract extension worth $69 million on December 13, 2007.
 Shortly after signing the deal, Richards was selected to represent the Eastern Conference at the 2008 NHL All-Star Game in Atlanta.
In the first NHL All-Star Game of his career, Richards registered an assist.

As the Flyers entered the 2008 Stanley Cup playoffs against the third-seeded Washington Capitals, Richards scored his first playoff goal on a penalty shot against Washington goaltender Cristobal Huet in Game 3.
In doing so, he became just the second player in NHL history to score his first playoff goal on a penalty shot (the first was Wayne Connolly who did so with the Minnesota North Stars in 1968).
The Flyers defeated the Capitals in seven games and then upset the Montreal Canadiens before falling to the Pittsburgh Penguins in the Eastern Conference Finals.
Richards finished his 2008 playoff run with 14 points in 17 games.

Before the start of the 2008–09 season, on September 17, 2008, Richards was named the 17th captain in Flyers history, succeeding previous captain Jason Smith, who had signed with the Ottawa Senators in the off-season.
 On February 15, 2009, Richards became the first player in NHL history to score three career three-on-five short-handed goals when he beat New York Rangers goaltender Henrik Lundqvist in a 5–2 win.
Six days later, on February 21, Richards became the first Flyer in team history to score a short-handed goal in three consecutive games and the first NHL player to do so since Joe Sakic in 1998.
 He finished the season second in team scoring to Jeff Carter with 80 points to go with a League-leading seven shorthanded goals.

Facing the Pittsburgh Penguins for the second consecutive year in the 2009 playoffs, Richards added five points in six games, but could not help the Flyers from being eliminated.
After Richards' season ended, he was announced as a finalist for the Frank J. Selke Trophy, awarded to the NHL's top defensive forward, along with Pavel Datsyuk of the Detroit Red Wings and Ryan Kesler of the Vancouver Canucks.
 The next day, on April 29, 2009, it was revealed that Richards required surgery on both shoulders.
He had reportedly felt discomfort since training camp and was on anti-inflammatory medication throughout the season.
Richards narrowly missed out on the Selke, which would have been Philadelphia's first individual player trophy since Eric Lindros won the Hart Memorial Trophy in 1995.
Datsyuk won the vote 945 to 942 in the closest Selke Trophy race since its inception.

The 2009–10 season started successfully for Richards, who scored five goals in his first three games, including his second career hat-trick in the second period of the Flyers' home opener against the Washington Capitals on October 6, 2009.
Against the Florida Panthers on October 24, Richards delivered a shoulder hit to David Booth's head.
Knocked unconscious, Booth fell awkwardly on his head and neck and had to be carried of the ice on a stretcher.
Richards was given a game misconduct, but was not suspended by the NHL.

From the outset of the season, Richards was involved in an
Richards made his NHL debut with the Flyers the following season, 2005–06, and scored a goal in his first game on October 5, 2005, against the New York Rangers. Later in the season, he scored his first career NHL hat-trick, which included two short-handed goals, against the New York Islanders on February 8, 2006. His hat-trick was the first by a Flyer rookie since Mikael Renberg on February 15, 1994.  Richards finished his NHL rookie season with 34 points in 79 games, third among Flyers rookies, behind Jeff Carter (drafted the same year as Richards, 11th overall) and R. J. Umberger, respectively.
Following an injury-shortened sophomore season – Richards was kept to 32 points in 59 games due to stomach surgery – Richards emerged as a star with the Flyers in 2007–08 and topped the team in scoring with 75 points. Recognizing his ascent as a leader on the team, Richards was named one of the Flyers' alternate captains at the outset of the season and was signed to a lengthy 12-year contract extension worth $69 million on December 13, 2007.  Shortly after signing the deal, Richards was selected to represent the Eastern Conference at the 2008 NHL All-Star Game in Atlanta. In the first NHL All-Star Game of his career, Richards registered an assist.
As the Flyers entered the 2008 Stanley Cup playoffs against the third-seeded Washington Capitals, Richards scored his first playoff goal on a penalty shot against Washington goaltender Cristobal Huet in Game 3. In doing so, he became just the second player in NHL history to score his first playoff goal on a penalty shot (the first was Wayne Connolly who did so with the Minnesota North Stars in 1968). The Flyers defeated the Capitals in seven games and then upset the Montreal Canadiens before falling to the Pittsburgh Penguins in the Eastern Conference Finals. Richards finished his 2008 playoff run with 14 points in 17 games.
Before the start of the 2008–09 season, on September 17, 2008, Richards was named the 17th captain in Flyers history, succeeding previous captain Jason Smith, who had signed with the Ottawa Senators in the off-season.  On February 15, 2009, Richards became the first player in NHL history to score three career three-on-five short-handed goals when he beat New York Rangers goaltender Henrik Lundqvist in a 5–2 win. Six days later, on February 21, Richards became the first Flyer in team history to score a short-handed goal in three consecutive games and the first NHL player to do so since Joe Sakic in 1998.  He finished the season second in team scoring to Jeff Carter with 80 points to go with a League-leading seven shorthanded goals.
Facing the Pittsburgh Penguins for the second consecutive year in the 2009 playoffs, Richards added five points in six games, but could not help the Flyers from being eliminated. After Richards' season ended, he was announced as a finalist for the Frank J. Selke Trophy, awarded to the NHL's top defensive forward, along with Pavel Datsyuk of the Detroit Red Wings and Ryan Kesler of the Vancouver Canucks.  The next day, on April 29, 2009, it was revealed that Richards required surgery on both shoulders. He had reportedly felt discomfort since training camp and was on anti-inflammatory medication throughout the season. Richards narrowly missed out on the Selke, which would have been Philadelphia's first individual player trophy since Eric Lindros won the Hart Memorial Trophy in 1995. Datsyuk won the vote 945 to 942 in the closest Selke Trophy race since its inception.
The 2009–10 season started successfully for Richards, who scored five goals in his first three games, including his second career hat-trick in the second period of the Flyers' home opener against the Washington Capitals on October 6, 2009. Against the Florida Panthers on October 24, Richards delivered a shoulder hit to David Booth's head. Knocked unconscious, Booth fell awkwardly on his head and neck and had to be carried of the ice on a stretcher. Richards was given a game misconduct, but was not suspended by the NHL.
From the outset of the season, Richards was involved in an 
Mike Richards