OAKLAND -- Brett Anderson and the A's walked away encouraged enough from his bullpen session Monday that he remains a possibility to start a potential Wild Card play-in game Friday.

"It went well, so we'll see how he feels tomorrow," manager Bob Melvin said. "You have to take that one day by day, but we were encouraged to see him throw all his pitches. He has a high intensity level in everything he does, so we came away encouraged."

Anderson, recovering from a strained right oblique, threw 50 pitches before Monday's game against the Rangers, with 30 coming in a warm-up session and 20 coming in simulated innings. Both Anderson and Melvin said Tuesday's recovery day will be a big indicator of when he'll be able to return, having pitched off a mound for the first time Monday since he went down with the injury Sept. 19.

The other likely option besides Anderson to pitch in the play-in game would be rookie Tommy Milone.

"I felt good today and my stuff was good," Anderson said. "It's a big day tomorrow, and I'll have my bullpen [Wednesday]. We have multiple options [for Friday], which is a good thing to have. I'll just control what I can control, and then we'll go from there."

"There's always that possibility, but we don't want to get ahead of ourselves," Melvin said. "We certainly don't want to push a guy if we feel like there's lingering soreness in that area. To this point there isn't, but you never know how he's going to feel after throwing a bullpen where he's throwing pretty hard."

Middle relievers front and center in A's success

OAKLAND -- Entering the last series of the season, the Oakland rotation's recent string of short outings has meant a bigger role for the bullpen, specifically the middle relievers.

Oakland starters have pitched fewer than five innings in nine of the last 14 games, with the rotation logging just one more inning than the bullpen (65 innings to 64) in that stretch, with the A's going 7-7.

"It's been pretty remarkable to see the innings that they have logged and the zeros that they have put up on the board," manager Bob Melvin said of his middle relieveres. "We feel like we do have a deep bullpen, we have our seventh, eighth, ninth [inning] guys that we rely on, and then we have our unsung heroes."

Melvin has had to depend on a group of bullpen arms led by Jerry Blevins, Pat Neshek, Evan Scribner, Jim Miller and Pedro Figueroa in between the starting rotation and the late-game trio of Sean Doolittle, Grant Balfour and Ryan Cook.

"We feel like we have some depth in our bullpen, and it's been coming into play recently," Melvin said. "You're going to have periods like that and you're going to have games where you'll have to go to the bullpen a little bit earlier, and these guys have been up for it."

The middle relievers have played an especially big role this season for an A's squad with a penchant for comeback and walk-off wins, having won eight games in which they trailed after seven innings as well as a league-best 14 walk-off wins.

"We absolutely feel that if we keep the game close and put up a zero, then we never count our offense out with all our late-game heroics," Blevins said. "As long as we put up a zero, we'll have a chance to win, no matter what."