Gregerson's move to the DL is retroactive to June 8. In his last relief appearance, he pitched two innings in the June 7 loss -- - walking three and striking out two.
"After that 18-inning game, I had a really hard time bouncing back I guess," Gregerson said. "I just tried to keep throwing through it, hoping it would get better."
Padres manager Bud Black said the move to the DL was to ensure that Gregerson didn't do further damage by trying to push through the pain.
"After the extra-inning game, he came in a little tender the next day," Black said. "We kept an eye on him and wanted to make sure that we didn't press him into any action if he wasn't feeling 100 percent or near it."
Gregerson has a 3.15 ERA in 30 appearances and has allowed only one run in his past 14 appearances.
Black said he decided to transfer Hill from the 15-day to the 60-day DL after it became clear he wouldn't be ready to return within a certain time frame. Hill, who was placed on the DL on April 26, has puzzled team doctors with inflammation in his right elbow.
"It opened up a roster spot for a couple of guys that aren't on the 40-man roster that we brought to the big leagues today," Black said. "I think it made sense from a procedural standpoint to do this, based on where Shawn was in his rehab."
Black said Banks could be "in the mix" as a starter candidate for Saturday's matchup with the Oakland A's. Banks was 3-4 with a 2.47 ERA in 14 appearances, including eight starts, for Portland.
"As of now, we're going to put Josh in the bullpen tonight with Ekstrom," Black said before Tuesday's game. "We'll see what plays out as the week goes on."
Amy Brittain is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.