Baker Mayfield finished up his collegiate career at Oklahoma – winning a Heisman Trophy and leading the Sooners to the College Football Playoff during his senior season. But the start to his college football career was a little more complicated, and this week, he opened up about it.Mayfield, who walked on at Texas Tech as a freshman, won five games for the Red Raiders before injuring his MCL against Kansas. But he says that after the injury, head coach Kliff Kingsbury turned on him, shutting him out of meetings.TMZ reports that Mayfield explains the situation on his new FOX Sports docu-series “All The Way Up.”Mayfield was also apparently upset that at the end of the year, he was not offered a scholarship. As a result, he left the team, sat out a year and enrolled at Oklahoma. He then walked on for the Sooners and became the team’s starting quarterback in short order.“It went from being ‘the guy’ for Coach Kingsbury … and then when I got hurt, it just changed a little bit … not a little bit, a lot.”“All the sudden it was as if I hadn’t played for him, hadn’t done anything for him. It was just different after I got hurt.”Baker’s father says the coach “completely withdrew his contact” with the QB after the injury — “He didn’t talk to Baker. He didn’t include Baker in the meetings.”Mayfield, once at Oklahoma, became a college football star. He won the starting job in 2015 and put together some incredible statistics over the next three years. This past April, he was drafted No. 1 overall by the Cleveland Browns.It’s safe to say that Kingsbury whiffed on this one. That said, he also probably gave Mayfield more than enough motivation to become the player he is today.