​49ers rookie defensive end Mikail Kamara, who was carted off the practice field Saturday, was diagnosed with a torn ACL, Matt Maiocco of NBC Sports Bay Area reports.The 49ers waived Kamara with an injury designation on Sunday, and he will revert to the team’s injured reserve list once he clears waivers.Kamara went undrafted out of Indiana, where he was named Defensive Player of the Game in last season’s College Football Playoff National Championship Game. He played six years for coach Curt Cignetti, four at James Madison and two more after transferring to Indiana when Cignetti became the Hoosiers’ head coach.The 49ers were expecting Kamara to compete for a roster spot as a pass rusher and a special teams contributor.