Ben Roethlisberger showed up a University of Pittsburgh practice last week and the big takeaway was that the Steelers' quarterback looked slimmer than ever.

According to Roethlisberger's agent, Ryan Tollner, the 34-year-old quarterback has shed at least 15 pounds thanks in part to a "high cardio" workout.

"He couldn't really work out because he kept getting hurt," Tollner told ESPN.com. "I think he said after the season, you know what, I'm going to lose weight to alleviate potential pain in my joints."

Roethlisberger missed four games last season with injuries to his knee and foot. He was also in the league's concussion protocol, and suffered a separated shoulder in the AFC wild-card game. In fact, in 12 NFL seasons, Big Ben has missed 10 games due to various ailments, though prior to last season, he hadn't missed a start since 2012.

And while Roethlisberger came into the league with the reputation for shaking off would-be tacklers, extending plays, and absorbing hits in the process, his game has evolved in recent years, thanks in part to offensive coordinator Todd Haley.

Roethlisberger was sacked just once every 23.5 pass attempts last season, the lowest rate of his NFL career. (By comparison, he was sacked once every 9.8 pass attempts as a rookie in 2004, and once every 12.8 pass attempts in 2011, Bruce Arians' last year as the team's offensive coordinator.) And as we saw during Big Ben's absence in 2015, the Steelers, even with a healthy Le'Veon Bell, Antonio Brown and Martavis Bryant, are only as good as their franchise quarterback.

Ben Roethlisberger has spent the offseason getting in shape for his 13th NFL season. (USATSI)
Ben Roethlisberger has spent the offseason getting in shape for his 13th NFL season. (USATSI)