Playing for a team with an established corps of post players, Missouri freshman forward Johnathan Williams III might have eased into college basketball. He could have been immersed slowly into a world where almost every opposing player he runs up against in the paint is as strong or stronger, as quick or quicker and every bit as talented. Williams, a smooth 6-foot-9 left-hander from Southwind High School in Memphis, Tenn., wasn’t afforded such a luxury. “Everybody’s talented and, especially in the SEC, everybody is very physical,” Williams said. “All the bigs are athletic. … So I’ve had to learn to play against tougher guys and more physical guys.” It’s been a baptism by fire for Williams, who has started all 25 games and averaged more than 26 minutes per game — more than any other Tigers frontcourt player this season. There have some tremendous moments, including Williams’ 17-rebound performance against Gardner Webb and a double-double (10 points and 15 boards) against UCLA. There also have been more than a few potholes, including a rough night when Missouri played at Vanderbilt, who comes calling on Mizzou Arena for a 7 p.m. tipoff Wednesday night. “It’s all about the physicalness of the game,” Missouri coach Frank Haith said. “For a young kid, a high school kid, going to college at this level, what you think would be a foul in high school is not necessarily a foul in college. Getting adjusted to that takes time.” During Williams’ first 15 college games, he made nearly half of his shots, but that shooting percentage took a nosedive after the struggles against the Commodores. Williams went three for eight in that Jan. 16 loss, blowing a couple of uncontested layups and banging a dunk hard off the back iron. His confidence shaken, Williams went through a stretch where he became tentative and had several shots blocked at the rim in multiple games.