The Bengals' injury report listed Johnson as "out" for the game. Johnson didn't practice on Thursday and wasn't available for interviews.
Johnson has been one of the NFL's most durable running backs since he became the full-time starter in 2004, replacing Corey Dillon. He has more carries over the last three seasons than any other running back.
If Johnson is sidelined, sixth-year running back Kenny Watson will make his first start since 2002 with the Washington Redskins. Watson has been primarily a special teams player and a third-down back in his five seasons with Cincinnati.
The running game is a main concern for Cincinnati (1-2), which can't afford to lose at home Monday night. The Bengals averaged only 2.8 yards per run during a 24-21 loss in Seattle on Sunday.
Johnson totaled only 9 yards on 17 carries before leaving the game with a strained hamstring. Watson gained 60 yards on nine carries, including an 8-yard touchdown run.
"He's not as bulky as Rudi is; he's a little bit quicker," quarterback Carson Palmer said Thursday. "He's not going to run people over like Rudi does and break through every arm tackle. But what he lacks in size and power, he makes up for in quickness and speed and great hands out of the backfield."
Copyright 2007 by The Associated Press