Williams sat on the sideline, his right leg wrapped from ankle to hip. He said it felt as if there was a golf ball-size knot in his hamstring.
Needing to fill Williams' 23.3 minutes and 13.7 points per game, the Sixers were expected to sign veteran guard Antonio Daniels to a 10-day contract on Monday night. That signing is expected to be a sort of insurance against rookie Evan Turner, who likely will play significant minutes in Williams' absence. If Turner fails to contribute adequately, the Sixers then would have a solid backup guard on the roster.
Daniels, 36, was scheduled to meet the team in Boston. He was flying from Texas, where he most recently played for the Texas Legends of the NBA Development League.
Sixers coach Doug Collins listed Daniels' qualifications: smart with the ball, good from the free-throw line, strong from beyond the arc, experienced, and mature.
"If you're going to bring somebody in, there's no need to bring in a younger player," Collins said. "We have enough youth on our team right now. If we're going to bring somebody in, it's somebody that we think can pick things up quickly."
Collins said Daniels would play some minutes in the next five games and that he could play as early as Tuesday night.
The Sixers still will turn to Turner, whose minutes have plummeted in recent weeks. Collins said Turner must pick up some of the slack.
"It's not like I'm not playing him because I don't like him," Collins said. "I'm trying to win games. My thing is, the minutes are going to be there. So be prepared and play well. The most important thing is that your teammates and your coaches can trust that you're going to play well. That's all we've asked him to do."
Resting. Swingman Andre Iguodala did not practice on Monday, but he is expected to play against the Celtics.
The homestand. After Tuesday's game, the Sixers return home for the final week of the season. Their regular-season schedule ends with games against the New York Knicks, Toronto Raptors, Orlando Magic, and Detroit Pistons.
If the regular season ended today, the Sixers (40-37) would face the Celtics (53-23) in the first round of the playoffs.
Contact staff writer Kate Fagan at email@example.com. Follow her on Twitter at twitter.com/DeepSixer3, and read her blog, Deep Sixer, on Philly.com.