He pitched a scoreless eighth inning with two strikeouts in Saturday's 8-4 loss to the Orioles, his first outing since July 14.
He made one rehab appearance for Triple-A Colorado Springs before rejoining the Rockies. Manager Walt Weiss talked to Betancourt to determine his mental and physical state before making him closer again. Left-hander Rex Brothers, who has 11 saves in 12 chances, will return to the primary setup role.
Betancourt, 38, said the appendectomy presented a challenge.
"It was kind of weird to be back on the mound," said Betancourt, who has gained back roughly four of the 10 pounds he lost after surgery. "It took some time to feel stronger again, but I'm fine now. I'm just happy to be back, especially after it first happened."
Said Weiss, "If there's a closing situation [on Saturday], we're going to give it to Raffy. It gives us some flexibility with Rex. If it's more of a left-handed inning, we can give it to Rex late as opposed to always having to wait for him to pitch at the end of the game."
The bullpen has worked best this season with Brothers and righty Matt Belisle setting up Betancourt, so Weiss wanted to go back to that plan, even though it's possible Brothers could move into the closer role next season. Both Betancourt and Belisle have mutual options for $4.25 million for 2014, and the Rockies haven't said if they will bring both, or either, back.
The Rockies plan to reduce their number of pitchers from 13 to 12 by the time they arrive in Philadelphia on Monday, after the Interleague series against the Orioles.
Corpas (1-2, 4.50 ERA) was the odd man out because Weiss felt the Rockies needed to carry three left-handers -- Brothers, Jeff Francis and Josh Outman, who has put together several strong outings recently.
"It was a tough choice," Weiss said. "Corpie has thrown the ball well. It comes down to numbers, and we like having a couple lefties in our bullpen going into Philly. It wasn't for lack of performance."