"That's why we're trying to be fairly conservative and put him on the DL now."
Graveman exited his Friday start prematurely because of general soreness but said he's since felt improvement. He planned to play catch Monday in preparation for a bullpen session later in the week.
The A's are not yet ready to announce a starter in his place.
"It's just one of those bumps in the roads you got to get over, and better now than let it kind of fester on for a couple more weeks," Graveman said. "I think if we give it a couple more days, then we'll be back to normal, back to where we need to be."
Graveman, who was on the mound for Opening Day two weeks ago, has been excellent in his three starts, allowing four earned runs across 18 innings for a 2.00 ERA. He made all 31 of his starts in 2016.
"It's frustrating, but then you look at it," Graveman said, "and now the goal changes to continue to make starts after this one, so hopefully that's the case and hopefully we get moving forward in the right direction and still can make 31 starts like I did last year, if not more."
Graveman's roster spot was given to Bruce Maxwell, meaning the A's have three catchers in tow. Recalled from Triple-A Nashville on Monday, Maxwell immediately drew a start behind the plate for Monday's series opener against Texas.
"If we have the ability to give Stephen [Vogt] some time off this year, we're going to do it," Melvin said. "He's a productive bat that we need to keep productive. If we can do this and give him a couple days off and DH him from time to time, we feel like longevity will be a little bit better for him to play healthy a little bit longer."
Maxwell, who hit .283 in 33 games in his big league debut last year, was coaching first base in the first inning for Nashville on Sunday and returned to the dugout to be told, "Hey, you don't have to coach first anymore."
"I was like, well, I don't have anything else to do," Maxwell said, "and they said, well, you're going to the big leagues, so go pack your stuff."
According to Melvin, Gray totaled 47 pitches in 2 2/3 innings in extended spring camp Monday. The right-hander, who is rehabbing a lat strain, remains on track to rejoin Oakland's rotation by the end of the month.
• A's general manager David Forst said Tommy John rehab patient Felix Doubront is being brought back as a reliever. Like Chris Bassitt, who also underwent the surgery last year, the left-handed Doubront is expected to be ready in June.