"I threw everything, and everything felt fine, so that's good news," Peavy said before the start of Wednesday's game against the Cubs at PETCO Park.
"Today, I really tested it. I let it go, threw everything close to game speed, and all of the pitches I would throw in a game."
Peavy has been on the 15-day disabled list with a strained right elbow since May 20, a move that was made retroactive to May 15, the day after he made his last start against Chicago at Wrigley Field.
His bullpen session was the first time he's thrown off the mound since that game against the Cubs. He had previously thrown off flat ground.
"Jake felt great, threw all his pitches ... fastball, slide and change," Padres manager Bud Black said. "We'll see how he feels tomorrow."
Black indicated that the reigning Cy Young Award winner will likely throw again either in a simulated game or in a Minor League rehabilitation assignment Saturday, though the likelihood of that seems less likely.
That could very well mean Peavy could return to the Padres starting rotation before the end of the current homestand, which ends on June 12.
"I'm sure we'll sit down and get a game plan to try to take it a step further," Peavy said. "I had to find out where we stand. I think I passed the test. It was a good day."
Peavy, who is 4-3 with a 2.91 ERA in nine starts, said that he threw 45 pitches during his throwing session on Wednesday.
Corey Brock is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.