SMU standout quarterback Preston Stone broke the fibula in his left leg during Saturday’s victory over Navy, Mustangs coach Rhett Lashlee said Monday.Stone was injured in the second quarter of the 59-14 win. He passed for 322 yards and three touchdowns before exiting due to the injury.”The team was disappointed for Preston,” Lashlee said of giving the squad the injury update. “Everybody is bummed. You work your tail off the way he did and just his development. You would love to be able to carry this through the end.”Kevin Jennings will take over as the starting quarterback.Stone’s injury represents a major blow for the Mustangs (10-2, 8-0), who meet Tulane (11-1, 8-0) in the American Athletic Conference title game on Saturday in New Orleans.The winner of the contest could land a New Year’s Six berth. Liberty (12-0) of Conference USA also is in the mix.