Marsh, who is from Bethel Park, Pa., made second-team all-Ivy as a freshman when he rushed for 526 yards and averaged 4.7 yards per carry. But the injuries started to pile up.
First came a broken right forearm in the second game of 2010 at Villanova. Then in the fourth contest of the 2011 season, Marsh was finishing up a three-touchdown performance against Fordham when he suffered a broken ankle in the fourth quarter.
Marsh was cleared to practice last spring, and Bagnoli, while remaining cautious, allowed him to take part in some contact drills. Now the coach is hopeful that when the Quakers begin preseason practice Aug. 20, the senior can remain injury-free.
"Obviously we're a deeper, more versatile, better team with Lyle than we are without him," Bagnoli said. "We're just hopeful that he will continue the improvement he showed last year and through the spring and that he can take that into the fall and stay healthy the entire year because he is a talented kid."
Marsh is part of a backfield with seniors Brandon Colavita, who rushed for 665 yards last season and has received all-Ivy recognition the last two years, and Jeff Jack.
If the running backs stay healthy, the Quakers, who finished 5-5 overall and 4-3 in the Ivy last year when they fell short of a third straight league championship, could be in good position to again challenge for the title.
Penn has another prolific runner in senior quarterback Billy Ragone, who gained 424 yards on the ground and scored seven touchdowns last season. Bagnoli said Ragone wasn't as effective a runner as he was in 2010 but said that was a function of the inconsistency of the offense as a group.
The coach said Ragone now has a better understanding of both the offense and his responsibilities as a leader, which could mean good things for the Quakers.
"We're optimistic that he can become one of the better quarterbacks, if not the best quarterback, in this league," he said. "He has that kind of ability level, and now we've just got to get some consistency out of him as well as out of the players around him."
Consistency is a goal on both sides of the football. Bagnoli called last year's disappointing record "one of those great life lessons, starting from me on down.
"I think our kids really went after the offseason program," he said. "I think our kids are excited, motivated, focused. They're reenergized. Hopefully that will translate toward getting things back on track."
Contact Joe Juliano at 215-854-4494 or jjuliano@phillynews.com or follow him on Twitter @joejulesinq