Parker broke a bone in his right hand at the end of the first half, putting a damper on the Spurs' 102-92 victory over the Memphis Grizzlies on Saturday night.
"He's got a broken hand. He'll be out six weeks," Spurs coach Gregg Popovich said. "He did it in the first half when he dove on the floor."
"We're playing well," Duncan said. "That is the one positive about the whole thing. We're going to have to get these guys to step up and step in and continue to play well.
"It hurts losing Tony, obviously. Hopefully, we'll find a way to get it done."
Parker broke the fourth metacarpal -- the bone between the bottom knuckle and wrist -- during a scramble for the ball near the end of the first half and did not return.
Meanwhile, the loss extended the Grizzlies' skid at home to eight straight.
"We've played a different caliber of teams away than we have at home," Memphis coach Lionel Hollins said. "We just haven't been able to raise our caliber of play. We execute better on the road. We make a better effort and better decisions on the road.
"At home, we haven't been able to do that."
O.J. Mayo led Memphis with 23 points, while Marc Gasol finished with 17 points and 13 rebounds. Zach Randolph had 15 points, and Rudy Gay 13, but the two were a combined 9 of 27, part of Memphis shooting 43 percent from the floor.
Memphis was within 91-85 with 5:36 left, but the Spurs scored the next seven points to get the advantage back to double digits.
From there, it was a matter of exchanging baskets the rest of the way for San Antonio to leave with a victory.
"They played real physical," Randolph said. "We didn't give the physical part back. They out-toughed us."
The Spurs shot 55 percent in the first half, and overcame an early deficit with a 20-4 run to open the second period. San Antonio would continue to extend the advantage as Bonner connected on a trio of 3-pointers, part of San Antonio hitting six of its first nine shots outside the arc.
Bonner also had the duty of guarding Randolph part of the night, trying to keep the Grizzlies' leading scorer from the block.
"My whole body hurts," Bonner said of banging against Randolph. "He plays hard. He plays physical. I felt every second of it."
San Antonio's defense caused 12 of Memphis' 15 turnovers in the first half as the Spurs led 58-48 at the break. Jefferson had 12 in the half, while Duncan and Bonner had 10 each.
Memphis chipped into the lead in the third period, but San Antonio was still ahead 78-72 entering the fourth.
While Memphis has dropped eight straight at home, they have won six straight on the road. The Grizzlies are the only team in NBA history to simultaneously have streaks of six-plus home losses and six-plus road wins, according to the Elias Sports Bureau.
"It's the strangest thing I've ever seen," Popovich said. "I have never seen anything like that. I really haven't.
"As far as home and away games, I thought it was really surprising. There's no way to explain that."
The game was the nightcap of a doubleheader at the FedExForum. The Memphis Tigers closed out their regular season with a 75-53 win over Tulsa in the Saturday matinee. ... Travel problems for San Antonio on Friday night delayed the Spurs leaving until Saturday morning, arriving in Memphis after noon, less than 7 hours before game time. The problem apparently was a light on a wing of their chartered flight. Popovich didn't take long to decide the Spurs would stay home and leave Saturday morning. "I wasn't going to wait two hours for them to tell me: 'I'm not sure this plane's going to go,' so we walked off." Two years ago, the Spurs were left on the tarmac overnight with plane problems in New Orleans after winning Game 7 of the Western Conference semifinals. ... Popovich has talked at times about giving Duncan some time off on the second night of back-to-backs. Despite that, Duncan was in the starting lineup against the Grizzlies. "As the month progresses," Popovich said, "I'm sure his time will get limited here and there." ... San Antonio's reserves outscored Memphis' 66-15, including 23-4 in the second quarter when the Spurs built their lead.