Pitcher Ryan Mattheus (Associated Press)

Ryan Mattheus will throw his first bullpen session since he broke his hand on May 19. Mattheus will jump on the mound ahead of schedule on Friday after playing catch from flat ground for the past two weeks. The right-handed reliever threw on Wednesday and will rest on Thursday before hitting the next milestone the next day.

“It feels great,” Mattheus said of his hand. “A lot better than I expected. No added soreness from Day One throwing. No added swelling. That’s great.”

Two weeks ago, Mattheus said he needed another four weeks before the bone could completely calcify and he could rebuild enough arm strength to return to the bullpen. Now, Mattheus will throw his first bullpen session on Friday and rest a day before throwing the next one. The next step in his return will depend on how his hand responds to the bullpen sessions. A rehab assignment could be part of his return.

Mattheus had a 4.96 ERA in 16 1/3 innings this season. After allowing five earned runs in an inning in San Diego two months ago, Mattheus punched his locker with his throwing hand and broke a bone. He had made peace with why he landed on the disabled list, but it doesn’t change how much he has longed to return.

“I never missed the game more than with Tommy John surgery,” he said. “This one was a little different. This one was self-inflicted and something I absolutely could have controlled. I’ve missed it a lot. I’ve felt like I’ve let the guys down and can’t contribute.”

The Nationals could be facing a surplus of relief arms when Mattheus is indeed ready to return. Right-handed reliever Christian Garcia is on a rehab assignment at Class AAA Syracuse.