A home matchup with the lowly Washington Wizards should help them regain their focus.
The Celtics look to win their sixth straight game at TD Garden and complete a season sweep of the Wizards on Sunday night.
Boston (25-22) failed to overtake Philadelphia for the top spot in the Atlantic Division with Friday's 99-86 road loss to the 76ers. The Celtics were outscored by 20 in the third quarter, and the team is attributing that to the shock after witnessing an apparent head injury to Pietrus.
The veteran swingman left on a stretcher and was hospitalized after an awkward collision late in the first half. He was listed as having a questionable closed head injury after landing hard on his tailbone and his head nearly smacked the court. He instantly clutched the back of his head with both hands and rolled over on his side.
"It looked awful," coach Doc Rivers said. "I just saw his neck snap. You knew that was bad. He was throwing up on the floor, so that's not very good either.
"I thought the injury, fatigue, everything, kind of all caught up to us."
It's unclear when Pietrus will be back, leaving the Celtics without one of their top reserves. He was averaging 9.6 points on 56.7 percent from the floor - 11 for 20 from beyond the arc - in the five games prior to getting hurt.
Boston should benefit from a return home, where it has won 10 of 12, including five in a row while averaging 105.0 points.
The Celtics have won 11 of the last 14 meetings with Washington, and six of seven at home following a 100-92 victory on Jan. 2.
Paul Pierce had 37 points, 10 assists and eight rebounds in Boston's 100-94 victory at Washington (11-36) on Jan. 22, putting the Celtics in position to sweep this four-game season series.
Pierce, the team leader at 18.5 points per game, is coming off a pair of impressive shooting performances while totaling 45 points. The 10-time All-Star forward has made 17 of 26 field goals - 6 of 7 3-pointers - while accumulating 18 rebounds in that span.
John Wall has had a completely different experience lately for the Wizards, making 10 of 34 from the floor while averaging 12.0 points over the last three games. He was a woeful 1-for-10 from the field and missed a potential game-tying 3 at the buzzer in Saturday's 95-92 loss to Atlanta.
"They gave me my shots. I just missed them," said Wall, who leads the Wizards with 17.3 points per game.
Wall's visit to Boston in January produced similar results, as he made 4 of 13 field goals for 11 points with eight assists. However, he had 27 points and 10 rebounds against the Celtics at home later that month.
Nene has topped 20 points and 10 boards in two of his three games with Washington since being acquired from Denver in a three-team trade last week. The forward-center had 21 points on 9-of-13 shooting and 11 rebounds against the Hawks.