Stults jammed the thumb making a defensive play in the fifth inning of his start Friday night in Florida. He had a light bullpen session Tuesday and said the injury felt much improved, but after 20 minutes, the thumb tightened up.
"It's not worth jeopardizing the team and the next start if it flares up," said Stults, who is 4-1 with a 3.82 ERA since being recalled to replace the injured Hiroki Kuroda. "It's in the best interests of the team and me, with Weaver available. It isn't worth the risk."
Manager Joe Torre made the decision during batting practice, even though Stults said he felt well enough to pitch. The Dodgers are 6-1 in his starts.
"I am disappointed," Stults said. "Selfishly, I want to pitch, but I don't want to get two batters into the game and I'm done and then have to miss my next start. It's a tough decision for me because I was throwing well, but it's just not ready. The stiffness was there 20 minutes after I threw."
Stults was injured while fielding a bunt, jamming his left thumb when his momentum after making a flip of the ball to first base put him into a headfirst dive on the infield grass.
Weaver, who like Stults opened the season at Triple-A Albuquerque, is 1-0 with a 3.60 ERA in two starts and 1-1 with a 3.00 in three relief appearances. He replaced fifth starter James McDonald for those two starts, then moved back in to the bullpen when Eric Milton was called up. Milton, coming off Tommy John elbow ligament replacement surgery, made his first start in two years Saturday night and would have been pitching on three days' rest if he had made the start Wednesday.
Instead, Torre said Milton will be skipped. Stults probably will return to the rotation Monday at Colorado.
In other pitcher injury news, Kuroda is scheduled to make an injury rehab start for Class A Inland Empire on Friday night, which puts him on schedule to return to the rotation the first week of June. That means he will miss two months with a strained oblique muscle suffered in a bullpen session two days after his Opening Day victory.
Jason Schmidt, who had a rehab start for Inland Empire on Sunday, will make his next start Saturday for Triple-A Albuquerque.
Hong-Chih Kuo, sidelined April 30, has resumed throwing and participating in drills with the club.
Ken Gurnick is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.