The 7-foot-1 Austin, who averaged 13 points and 8.3 rebounds as a freshman, said he initially injured the shoulder in Big 12 play. However, it became so painful after the season that it made his decision to remain in college for another season a no-brainer.
"I wouldn't have been able to work out for teams," Austin said. "I could barely lift five pounds."
However, Austin said that it wasn't a certainty that he would have left school, even if he had been healthy heading into the NBA draft process.
"I know I needed to mature," Austin said. "That's one of the reasons I came back. To mature and be a leader. I needed a year of growing up -- and I didn't want to grow up in the NBA."
Austin came into college weighing 208 pounds and said he is now approaching 225.
"People say I'm not tough, but what people don't realize is that I was the team leader in rebounds," Austin said. "But I'm going to be a different player this season. Way better -- because of my mindset."
Austin was regarded by some as a lottery pick when he arrived at Baylor, and he said the feedback he received was that he would have gone somewhere in the latter half of the lottery if he had left school after one season.
The long and skilled Austin has drawn criticism for his tendency to roam on the perimeter and shoot 3's. He took 90 shots from beyond the arc last season, nearly 25 percent of his overall shot attempts.
"That's still a big part of my game," he said. "I can play out there, but I want to play both ends -- inside and on the perimeter."
Austin is one of four starters back from a Bears team that went 23-14 and earned a trip to the NIT. Baylor lost starting point guard Pierre Jackson, who averaged team highs of 19.8 points and 7.1 assists per game.