Hill was 8-3 with a 2.25 ERA in 11 starts before suffering a left groin strain that sidelined him for nearly five weeks.
"Similar to the Reddick situation, you're getting a guy back that was pitching like a No. 1," A's manager Bob Melvin said. "I felt like both those guys were on their way to All-Star nods. To lose both those guys, we felt it, so to be able to get both those guys back in a timely fashion when we're playing pretty decent, hopefully that gives us a little more consistency and we can sustain what we've been doing here recently."
Hill made one Minor League rehab start with Class A Advanced Stockton on Monday, throwing 66 pitches in three-plus innings and allowing one run on four hits with six strikeouts. The veteran pitcher rejoined the A's in San Francisco on Tuesday and said he had "no issues" during the outing.
"Just getting through it and being healthy, I'm looking forward to Saturday now," Hill said. "It's an injury I haven't dealt with before, so it's good to get through it and just keep moving."
Hill's arrival will likely prompt the A's to send down rookie Dillon Overton. The young left-hander earned the win against the Angels in his first big league start Saturday with 5 2/3 innings of three-run ball to follow the lead of fellow rookie Daniel Mengden, who has greatly impressed in four starts.
"Maybe these guys were targeted to be here a little bit later, maybe next year, maybe in September, but to gain this experience, even if a couple of them are around for a short period of time, I think is important going forward, because we feel like we have some position players on the rise who are going to be here pretty soon, maybe next year," Melvin said. "Couple that with some of these pitchers that are getting experience now, they'll be further along next year. Not only are they getting experience, they're performing pretty well, too."
"It's been awesome to see," Hill said. "Just the way that the guys have gone out there and pitched with conviction and gone after it, that's really what you want to see, just taking advantage of the opportunity that's here."
Jane Lee has covered the A's for MLB.com since 2010.