Riding around campus the last couple of days on a motorized cart, it’s obvious the injury to Willie Cauley-Stein’s left ankle was more than just a sprain.John Calipari said as much Thursday during a press conference for his new book, “Players First: Coaching from the Inside Out,” when he confirmed that Cauley-Stein went under the knife recently to fix the injury.”He did have surgery,” Calipari said. “The best doctor in the world to do it, kind of like we did with Nerlens (Noel).”Calipari expects Cauley-Stein to be off the motorized cart and back in the gym in a “couple months.””He’ll be fine,” Coach Cal said.As for who did the surgery and what exactly the injury was that knocked Cauley-Stein out for most of the last four games of the NCAA Tournament, Calipari wasn’t disclosing that information Thursday.”They got knee guys, they got ankle guys, they got shoulder people, they got elbow people. (The doctor who did the surgery) was with the best that there is in the world to have the thing done,” Coach Cal said. “And it was a procedure that is done a lot.”Whether it was the ankle injury that would prevent him from working out for NBA teams, falling a win short of a national championship, or tasting a Final Four but not being able to play in it, Cauley-Stein shocked a lot of people earlier in the week when he announced he was returning for his junior season at Kentucky.Among the surprised was his college head coach.”Raise your hand if you were stunned that he said he was coming back,” Calipari said as he raised his own hand.Calipari said he never talked to Cauley-Stein about coming back to school. He said their only conversation was about the first time he visited Cauley-Stein at his high school and how amazing it was that a kid who was involved in just about every sport but basketball could now be a first-round pick after just two years.”Can you imagine?” Coach Cal said. “And that was our talk.”It was Cauley-Stein who approached Calipari about returning.”He basically said, ‘You know, Coach, I’m in no hurry to leave. I love going to school. I’m gonna be really close to my degree. I still have to grow as a player. And we left something on the table there that I’d like to try and get.’ That’s a good answer for me if you want to come back,” Calipari said.