Backup quarterback Kyle Boller took all the repetitions again Friday with the first-team offense.
McNair missed the second game of the season with a groin pull that has hampered him since the season opener in Cincinnati.
"It's just tightened up," Ravens coach Brian Billick said of McNair's back. "I'm not sure the groin didn't lead to some tightness in the back. We'll have to see how he feels at the end of the day today, Saturday and Sunday -- game-time decision."
McNair spoke briefly in the locker room on his way to treatment. Asked if he would be available to start Sunday, McNair said, regarding his back: "It's OK. We'll see. If I can't go, then we've got a good backup in Kyle."
Boller, who has completed 33 of 51 passes for 287 yards, two touchdowns and one interception, engineered a 20-13 victory over the New York Jets in his lone start.
"I've gotten a lot of reps in practice and offensively been really into the game plan and watching it on tape. I'll be ready," Boller said. "If he can't go, then I'll just step in there."
Billick emphasized that there was no quarterback controversy.
"Steve McNair is now, and will be, my starting quarterback, for as long as he can go," Billick said.
Copyright 2007 by The Associated Press. All Rights Reserved.