OAKLAND -- The A's reliance on young arms in the bullpen hasn't been more evident than in the team's past two games. Rookie Sean Doolittle closed out the team's win on Saturday, and rookie closer Ryan Cook entered his familiar role in the ninth on Friday -- and though Cook blew the save then, he's been lights-out most of the year.

But young arms are precious and fragile commodities, and A's manager Bob Melvin has noted in recent days that the team will be watching the innings of pitchers like Doolittle and Cook, as well as the trio of rookies in the starting rotation. Doolittle's is an especially unique situation, since he didn't begin pitching professionally until last year.

Melvin's comments were spurred by the fact that this week marked the first time Doolittle pitched in back-to-back games, and Cook in three straight. It could potentially be a problematic area -- the pair has pitched very well, and any manager wants his best hurlers to be available as much as possible.

Still, Melvin said it isn't difficult to decide to hold out his young pitchers because the team is well aware of how important their future is, too. And Doolittle and Cook agreed, saying before Saturday's and Sunday's games, respectively, that they trust Melvin to make the best call.

"At the same time, there have been times where it's frustrating, where I feel good enough to go, and because they're being careful," Doolittle said. "But at the end of the day, I understand that on some level their hands are tied.

"We'll see how it plays out, but I understand the uniqueness of the situation."

Another dynamic, at least for Cook, is how his performance has suffered when used a lot. He hasn't allowed a run in 33 innings pitched with at least one day's rest, while he's given up eight runs in 7 1/3 innings with no rest.

Cook insisted he hasn't felt any different physically when pitching without rest, and pointed to it just being a small sample size.

Anderson makes key stride toward return to A's

OAKLAND -- Fresh off his first rehab start since undergoing Tommy John surgery, A's lefty Brett Anderson said concern has finally shifted from his arm to his performance.

"It's good to get in some baseball scenarios I haven't been able to get in in the past year," he said Sunday morning. "I can start worrying about what my pitches are doing rather than how my arm's feeling."

Anderson pitched two innings for Class A Stockton on Saturday, throwing 35 pitches and allowing two runs on four hits. He also hit a batter in an outing where the results weren't exceptional, but more importantly, the way he felt after was.

"I felt good," he said. "Results were kind of so-so, which is expected. But as a baseball player and perfectionist, you want to get everyone out and have your stuff and command be awesome and where you want it to be, but that's unrealistic at this point. It's a big step just to get back on the mound and in a game."

The 24-year-old Anderson is set to throw a bullpen session on Monday, and barring any setbacks, he will likely make his next start with Stockton on Thursday in Visalia, Calif. He'll throw around 45-60 pitches, as he continues to build up innings in an effort to return to an A's rotation that is thriving.

Entering Sunday, A's starters -- of five, three are rookies -- had allowed two runs or fewer in 24 of the last 31 games, leading to 22 team victories in that span.

"The way our staff's been, I'm going to be making the Triple-A playoff push," Anderson joked. "You see what guys are doing up here, and you want to be a part of it. And once you are up here, you want to keep with the trend they've been setting all year."

Worth noting

• Melvin said before Sunday's game that right-hander Brandon McCarthy will throw a three-inning simulated game on Wednesday at the team's complex in Arizona. McCarthy has been on the 15-day disabled list since June 20 with his reoccurring right shoulder soreness.

• Center fielder Coco Crisp was out of the starting lineup on Sunday, with Melvin wanting to get him his first day off since returning from left shoulder soreness on Tuesday. Crisp was still available to appear in the game. Yoenis Cespedes slid over from left to take Crisp's spot, and Seth Smith got a rare start against a left-hander in left field.