Rehab progressing for Los Angeles Dodgers pitchers Brandon McCarthy, Hyun-Jin Ryu

Brandon McCarthy and Hyun-Jin Ryu, the Dodgers’ surgically repaired pitchers rehabilitating toward a return this summer, are closing in on facing hitters.

McCarthy, who underwent elbow ligament replacement surgery 13 months ago, completed a bullpen session Monday at Dodger Stadium with Manager Dave Roberts standing in the batter’s box. McCarthy’s fastball registered about 89 mph, Roberts said.

The next step for McCarthy would be to face hitters in a controlled environment. A similar schedule awaits Ryu, who sat out last season after surgery on his left labrum. Ryu is expected to throw another bullpen session Tuesday. After that, he also can face hitters.

“When you’re rehabbing, it’s tough to be rehabbing,” Roberts said before the Dodgers opened a four-game series against the New York Mets. “But when you have somebody who is around, and you can push each other, it makes it a little easier. They’re on similar schedules. So I would think it makes it a little bit easier. They’re both doing well.”

Roberts mentioned last month that he thought McCarthy and Ryu would return to the majors within a week of each other. That could change due to complications along the way, but the duo is inching closer to minor league rehabilitation assignments.

It is unclear how the Dodgers would make room for the pair, if their other starters remain injury-free, but Alex Wood and Ross Stripling could aid the team as relievers.

Fien to triple A

The Dodgers optioned right-handed reliever Casey Fien to triple-A Oklahoma City, meaning they will not alter the composition of the bullpen. Roberts said he planned to use Pedro Baez as his best option for high-leverage spots in either the seventh or eighth inning, depending on matchups.

The team claimed Fien off waivers from the Minnesota Twins last week. In 13 2/3 innings with the Twins this season, Fien gave up 12 runs.

Andy.mccullough@latimes.com

Twitter: @McCulloughTimes