Ledezma, who was 0-2 with a 5.04 ERA in 14 games, struggled mightily with command, especially over his six starts, where he was 0-2 with a 6.57 ERA.
San Diego has recalled left-handed reliever Joe Thatcher to take Ledezma's spot on the 25-man roster. Thatcher is 0-4 with a 7.45 ERA in 17 games with San Diego this season. He had a 2.00 ERA in eight games with Triple-A Portland.
The Padres have 10 days to trade, release or place Ledezma on waivers.
"Wil has thrown the ball well at times, and at other times, he wasn't so consistent," Padres manager Bud Black said. "I think there were flashes of what we think that Wil can do. It could [still] crystallize for him."
It just might not be with the Padres, who traded reliever Royce Ring to the Braves last July for Ledezma.
Ledezma appeared in only nine games following the trade. Ledezma worked closely with pitching coach Darren Balsley in Spring Training on his delivery in order to improve his command.
It looked like it had worked, as Ledezma had a 3.15 ERA in his first eight relief outings this season. But he struggled once he went into the starting rotation.
In his final game as a Padre, Ledezma allowed five runs on six hits over four innings in earning a no-decision on Sunday in a game San Diego won 8-6.
"He's put in the work, he's tried to do a number of things Darren has suggested," Black said. "It just hasn't happened consistently. He'll be the first to tell you that he needs the consistency to be the pitcher he wants to."
Corey Brock is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.