Macomb, Ill.—Usually football coaches have a pretty good idea of who’s going to be starting. A few positions may be up for grabs, but for the most part it’s simple math. For the St. Louis Rams, the starting offensive line has resembled a game of musical chairs. Starting left tackle Orlando Pace isn’t in camp because of a contract dispute, starting center Dave Wohlabaugh is out for at least three months with a hip injury and starting right tackle Kyle Turley could be out another three weeks with a sore back. As it stands, Andy McCollum, who was the starting left guard last season, has been moved to center. Scott Tercero, who started Thursday night’s pre-season game at right tackle, has been inserted into the left guard spot, moving Adam King to second-string right tackle. At right guard, the only spot not in question is anchored by Adam Timmerman. Grant Williams is filling in at the left tackle, while the Rams await Pace’s return. Williams is expected to move to right tackle when that happens. In the meantime, Greg Randall, who started 16 games with the Texans last season, is playing with the No. 1 unit at right tackle. Confused yet? Imagine trying to sort this mess out. That’s offensive line coach John Matsko’s job. He seems to be taking the task in stride, saying Tuesday, “It’s a challenge and it’s a challenge that we accept. When you get in the National Football League, you know holdouts and injuries are a part of the deal.” Matsko seems to enjoy the challenge of getting these players ready to perform in crucial situations, even though some of them will be relegated to the bench in the coming months, saying, “You’re motivating to get a game-day performance on a daily basis because when you put your hand on the ground you gotta do it like you’re gonna do it on Sunday.” With all the new players filling the shoes of familiar ones, Matsko says he has to be more than just the guy blowing a whistle, “A coach in the National Football League is basically three things: he’s a teacher, he’s a counselor and he’s a role model.” And a juggler.