Napoli said he's being careful with it, not wanting to aggravate the injury so seriously that it would knock him out for the rest of the season.
"I need to get healthy," Napoli said. "I'm not going to aggravate it if I feel tight like this."
Napoli said he's been hitting every day and isn't too concerned about getting his timing and rhythm back. But he also said he doesn't want to play until he's ready to go all out.
"Once I get in a game," he said, "my instincts are going to take over and I'll go first to third. I want to be ready."
Napoli is batting .253 with nine homers and 31 RBIs, his .459 slugging percentage fourth among regulars on the club.
In Napoli's absence, Jeff Mathis has flourished defensively while delivering some timely hits as the everyday receiver, with Ryan Budde in reserve.
Mathis is coming off one of his finest efforts, taking Felix Hernandez deep on Wednesday for his second homer of the season and fourth in the Majors, while guiding Jered Weaver through eight superb innings in a victory over Seattle.
Calling it "gratifying and uplifting," Mathis caught all three games in the crucial sweep of the Mariners and excelled, handling John Lackey's shutout in the opener.
"Just to relax and have fun playing the game I've played for so long ... it's very liberating," Mathis said. "I learned a lot from last year. I came to play the game and not worry about making mistakes and trying to impress people."
When Mathis fumbled away an opportunity to be the club's No. 1 catcher last year, Napoli, his good buddy, emerged as a potential star. Mathis has eight RBIs in his past nine games, showing no wear and tear after starting 30 of the past 34 games.
"Jeff's played very well," Scioscia said. "But it's going to be tough for one catcher to carry the burden of playing every day. We're going to need them all. We need depth."
Bartolo Colon yielded three runs, all in his final inning of work, as he went five innings and struck out four men in a 5-4 win by Triple-A Salt Lake over Fresno on Thursday.
Colon will make one more start for Salt Lake, on Wednesday in the Pacific Coast League playoffs, and then is expected to rejoin the Angels' staff -- and possibly the rotation as the fifth starter.
"Very good reports on Colon," Scioscia said. "He pitched well, and his velocity was good. He carried through to almost 70 pitches, which was good. He took a step forward, definitely. Hopefully, he'll be in the 85- to 90-pitch range on Wednesday. It'll be a good test for him."
Scioscia said a decision has not been made on Monday's starter against the A's. It is Ervin Santana's spot in the rotation, but he has struggled his past two starts.
Dustin Moseley, who pitched 5 1/3 scoreless innings in relief of Santana in Seattle, is a candidate. Another option is having Weaver work on his regular fifth day coming off a superb effort against the Mariners.
For the first time since bruising a bone on the outside of his left wrist swinging the bat against the Yankees on Aug. 21, Chone Figgins had a bat in his hands, taking swings from the left side at balls on a tee. The AL's fourth leading hitter at .335, Figgins said it "went all right" -- but he's not ready to play again.
"I'm making progress," he said. "But it's still sore in there. I'm just happy I can do this. After it happened, I was worried I wouldn't be able to play at all."
Rivera due Sunday:
Outfielder Juan Rivera is expected to rejoin the Angels on Sunday after breaking his left tibia in a winter baserunning incident in Venezuela. He had surgery on Dec. 27 and began the long comeback during Spring Training.
Rivera has 12 RBIs in 13 games for Triple-A Salt Lake, hitting .235. He hit .310 for the Angels last year, with 23 homers and 85 RBIs in 124 games. Given his long layoff, he figures to serve as a right-handed bat off the bench.
Pitching depth on the way:
Scioscia said the club is focusing on pitching with its Sept. 1 callups.
Outrighting right-hander Steven Shell to Salt Lake on Friday, the Angels opened a spot on the 40-man roster that could go to another Salt Lake right-hander, Jason Bulger. In 49 relief appearances, Bulger has 81 strikeouts against 25 walks across 53 2/3 innings, going 5-2 with a 3.69 ERA and 10 saves.
On Aug. 31 in Angels history:
Nolan Ryan delivered his third straight shutout in 1972, beating Detroit, 4-0. The Express gave up three singles and two walks, striking out 10. First baseman Bob Oliver, father of Angels lefty Darren Oliver, had two hits and drove in a run in support of Ryan.
Kelvim Escobar (15-6, 2.77 ERA) faces right-hander Edinson Volquez in his 2007 debut for the Rangers in Saturday's 12:55 p.m. PT matinee at Angel Stadium.