Williams, who hadn't played since 2005, carried the ball just six times for 15 yards before he was hurt in the second quarter of a 3-0 loss to the Pittsburgh Steelers Monday night.
The move to IR was expected.
Miami started Williams after just a week of practice that followed an 18-month suspension for violating the NFL's substance-abuse policy.
"It's unfortunate, but as he and I talked it's another test for him, another obstacle for him to overcome, and he knows we're going to support him," Coach Cam Cameron said.
Williams rushed for 743 yards for the Dolphins in the 2005 season, during which he sat out a four-game suspension for violating the drug policy.
In 2002 with Miami, the 1998 Heisman Trophy winner led the league with 1,853 yards.