ANAHEIM -- Angels lefty Tyler Skaggs threw a bullpen session on Saturday, marking the first time he’s thrown off a mound since suffering a sprained left ankle on April 12.

The Angels remain hopeful that Skaggs, who is on the injured list retroactive to April 13, will be ready to be activated once eligible on Tuesday. But the Angels are still working out when he’d make his next start, as they have to make sure he comes out of the bullpen session feeling good.

Skaggs didn’t comment after throwing in the Angels’ bullpen, but flashed a thumbs up sign to the media when asked how it went.

Skaggs suffered the injury while trying to field a bunt attempt from the Cubs’ Kyle Schwarber in the fourth inning of his start but finished his inning before coming out of the game. He was diagnosed with a Grade 1 left ankle sprain.

Skaggs, 27, has posted a 4.20 ERA with 14 strikeouts, seven walks and four homers allowed in 15 innings over four starts this year.

Heaney progressing

Lefty Andrew Heaney, on the 10-day injured list with left elbow inflammation, is nearing a bullpen session, and manager Brad Ausmus said it should come within the next week. Heaney hasn’t pitched since March 8 in a Spring Training game, as he complained of discomfort after that outing and was shut down.

But Heaney has been able to throw without any issues after getting a cortisone shot in early April, as he restarted his throwing program on April 8. The Angels have not given a timetable for his return.

“All positive so far, no issues,” Ausmus said.

Bard recalled, Peters optioned

The Angels recalled right-handed reliever Luke Bard from Triple-A Salt Lake before Saturday’s game against the Mariners and optioned left-handed reliever Dillon Peters to Triple-A to make room for him on the roster. It’s Bard’s second stint in the Majors this season, as he's posted a 4.76 ERA with five strikeouts and two homers allowed in 5 2/3 innings. But he's pitched well at Triple-A, throwing three scoreless frames with seven strikeouts.

“Bard’s been pitching really well, that’s basically it,” Ausmus said.

Peters, meanwhile, made three appearances in his first stint with the Angels, allowing one run on three hits over three innings. He pitched on both Thursday and Friday, which made him unavailable for Saturday, which is why he was sent down.

Reliever Justin Anderson remains at Triple-A, as he pitched on Friday, striking out four batters in 1 1/3 scoreless innings. It was his first scoreless outing at Triple-A, as he had previously surrendered five runs in 2 1/3 innings. But he had a 0.00 ERA in 5 2/3 innings with the Angels before being sent down, so he's expected to be recalled soon.

Tropeano nearing activation

Right-hander Nick Tropeano, who opened the year on the injured list with a right shoulder strain, was stretched out to four innings in a simulated game in Arizona on Saturday. The Angels still haven’t determined what role Tropeano will return in, but he’s likely to be sent to Triple-A Salt Lake as a starter once healthy to give the Angels rotation depth.

Bour discipline to be handled in-house

Ausmus wouldn’t say if first baseman Justin Bour will face any discipline for failing to run to first base on a pop-up in the eighth inning of Friday’s 5-3 loss. The Mariners started a double play because Bour didn’t run, which ended the inning and shifted the momentum back in Seattle’s favor.

Bour wasn’t in the lineup on Saturday, but he wasn’t expected to start with lefty Yusei Kikuchi on the mound for the Mariners.

“We’ll handle that in-house,” Ausmus said. “That’s not something that we deal with publicly.”