Scribner, 30, suffered a tear in the same muscle in 2011 while pitching in the Padres organization. He finished his 2015 campaign with a 4.35 ERA in 54 appearances with 14 home runs allowed -- most in the Majors among relievers.
The right-hander posted a 2.01 ERA over his first 27 games but had a 6.91 ERA over his last 27 contests.
• Right-hander Cody Martin, who lost to the Angels on Tuesday after allowing five runs on six hits in three innings, was optioned to Triple-A Nashville on Wednesday.
Melvin was not ready to announce who would next start in that spot.
"We have something in mind but won't make an announcement on it yet," Melvin said. "This was probably going to happen regardless of how he pitched. But it was good to be able to see him firsthand and get him out on the mound, here locally too. I know he had a bunch of family and friends in the stands last night."