STANFORD, Calif. -- Josh Nunes is determined not to let the painful end to his Stanford football career be his lasting legacy.

The former starting quarterback retired from the sport Monday after a complete tear of his right chest muscle, ending a collegiate career filled with dramatic highs and devastating injuries.

Nunes' father, Tim, told The Associated Press that his son ruptured his pectoralis major tendon while doing his normal bench press routine during an offseason workout in February. He dropped the weights on his chest -- although the tendon had already ruptured -- and had surgery a few days later to reattach the tendon with screws.

No further damage was caused by dropping the weights other than some bumps and bruises. Nunes is expected to make a full recovery, which can take up to 12 months following surgery, but it's not worth risking an even more serious injury.

"The injury shouldn't have happened, and we're not sure why it happened," Tim Nunes said. "It's not something that could've been prevented. Doctors told us it's rare for quarterbacks. Just a freak accident."

Josh Nunes is finishing his bachelor's degree in management science and engineering. He already has been accepted into the master's program at Stanford for social psychology.

"I don't think you've heard the last of him," his father said.

The odd injury wasn't Nunes' first on The Farm.

In the third practice of training camp in 2011, Nunes dropped back to pass and stepped on running back Andrew Stutz's foot, tore a ligament underneath his right big toe, was in a boot through the first five games, and had a steel plate that was completely rigid in his shoe when he returned to practice. He never played a down.

Then, Nunes beat out Brett Nottingham in an eight-month quarterback competition. But he faced near-impossible expectations last season while succeeding record-setting quarterback Andrew Luck, the No. 1 overall draft pick of the Indianapolis Colts last April.

Nunes played spectacularly in the second half to upset then-No. 2 Southern California and rallied the Cardinal from a two-touchdown deficit for a 54-48 overtime win against Arizona, but he struggled for long stretches in close losses at Washington and Notre Dame, with the offense failing to score a touchdown each time.

Kevin Hogan's role increased more each week, starting with Wildcat and read-option packages, then moving into the prototypical sets of Stanford's complicated offense. Finally, after Nunes failed to move the offense on the first two possessions at Pac-12 cellar-dweller Colorado, Hogan entered in relief and never relented -- leading the Cardinal's remarkable run to a Rose Bowl victory over Wisconsin.

Nunes completed 52.8 percent of his passes and threw for 1,643 yards, 10 touchdowns and seven interceptions last season. The junior was likely to be Hogan's backup this season. Freshmen Evan Crower and Dallas Lloyd will compete for the No. 2 spot on depth chart.

Stanford also announced Monday that fullback Geoff Meinken was not going to return for a fifth year of eligibility because of a knee injury.