That's what Hill did Wednesday morning, throwing 50-plus pitches with hitters standing in. The veteran will travel with the team to Anaheim on Wednesday evening and throw a bullpen session there Friday.
Barring any setbacks with a left groin injury that has sidelined him for nearly a month, Hill will be cleared for a rehab start of roughly 65 pitches with Class A Advanced Stockton.
"I hope that's the only one," Melvin said. "He did go after it really hard, as he does all the time."
Hill was the A's best starter at the time of his injury, pitching to an 8-3 record and 2.25 ERA in 11 starts, and his return would be significant for a beleaguered rotation that's also hoping to get back lefty Sean Manaea (forearm) next week.
The club has yet to announce a starter for Friday's road contest in Anaheim.
Jane Lee has covered the A's for MLB.com since 2010.