SAN DIEGO -- After pitching three scoreless innings in a rehab start for Class A Lake Elsinore on Tuesday, Padres right-hander Andrew Cashner is ready to return from the disabled list and will likely start Sunday afternoon against the Yankees.

Cashner, who exited his June 10 start after just six pitches because of a strained neck, threw 38 pitches Tuesday night -- and 12 more in the bullpen -- with no issues.

"I don't think there's really any hesitation," Green said. "... The expectation is that he slides into that spot on normal rest on Sunday, and we push [Luis] Perdomo back for another day."

The Padres have toyed with the idea of going to a six-man rotation to give their pitchers a bit of a breather heading into the All-Star break. That option would mean Erik Johnson, who has struggled since being acquired from the White Sox in the James Shields trade, would maintain his rotation spot.

But the recent addition of Paul Clemens, who was claimed off waivers from the Marlins on Tuesday, could muddy that picture. The Padres will have to make a move to clear a roster spot for Clemens before Friday's opener against the Yankees, and they'll need to make another move on Sunday for Cashner.

"That's something we're still exploring at this point in time," Green said of the potential for a six-man rotation. "We obviously claimed Paul Clemens, and we're trying to see where he fits best. I think in the next couple days, we'll get some clarity on that."

In 11 starts this year, Cashner has posted a 4.75 ERA with a 1.45 WHIP. His stint on the disabled list was his second this season -- both of which barely lasted past the minimum 15 days. He also missed time in May because of a strained right hamstring.

As for Opening Day starter Tyson Ross, another ailing Padres righty, he's continuing to throw bullpen sessions and has progressed to doing so with small breaks throughout -- to simulate the time between innings.

In his recovery from shoulder inflammation, Ross' next step will be throwing live batting practice. But the Padres aren't putting a timetable on when he'll do that. They remain hopeful he'll be back shortly after the All-Star break.

"He's kind of our prized guy," Green said. "We're making sure that he's completely healthy. We've taken a very conservative route. I don't think at this point we're going to jump a step just to get him back a week quicker. There's really no incentive to that. So if he needs another time to throw an up-down session, we'll give him one more. We want to make sure he feels good and [is] confident before we move on to the next step."

AJ Cassavell covers the Padres for MLB.com. Follow him on Twitter @ajcassavell.