Chapman was held out of the club's first eight games after receiving a cortisone shot to relieve inflammation and bruising around the sesamoid bone in his right hand, but he anticipates getting enough at-bats to be ready for the regular season.
Infielder Jorge Mateo, meanwhile, remains out due to a left knee sprain. Though he's been participating in running drills, there's no timetable for him to make his spring debut.
Right-hander Ryan Dull (shoulder) will resume throwing on Sunday with a round of catch, per Melvin.
The A's rotation competition was on pause Saturday, as right-hander Kendall Graveman took the mound for his second Cactus League start. The results were less than ideal, but Graveman treated the outing as a learning experience after allowing four runs in just 1 1/3 innings.
Graveman, favored to make his second consecutive Opening Day start, opted not to throw on the club's off-day Friday, experimenting with a practice he's never subscribed to in preparation for a season that has several more off-days on the schedule.
"I didn't pick up a baseball [Friday]," Graveman said. "I've always thrown the day before to keep that arm slot, that feel. With the off-days this year, I wanted to kind of see how that worked out. The body felt great, but I think for me, personally, being the kind of pitcher that I am, I'm going to need to throw on those off-days if I'm going to start the day after. It's an overall feel thing, it's not an excuse."
As a group, A's starters have struggled this spring. Their top prospect, however, continues to dazzle. Lefty A.J. Puk fanned three over three innings in relief, allowing one unearned run. His ERA through five innings this spring remains zero.
"Up to 97 today," Melvin said. "Throwing the ball where he wants to, real smooth delivery, using all his pitches. It's been real impressive. He's the one guy that keeps putting up zeros for us."
Right-handers Frankie Montas and Chris Bassitt, who are gradually being stretched out to start, are among the pitchers scheduled to appear in Sunday's 12:05 p.m. PT road contest against the Padres, which can be heard on Gameday Audio. Relievers Blake Treinen, Chris Hatcher, Yusmeiro Petit and Danny Coulombe are also expected to get in the game.
Jane Lee has covered the A's for MLB.com since 2010.