Reliever Keith Foulke said he will throw 30 pitches Monday at Triple-A Sacramento, and starter Rich Harden is scheduled to make his second rehab start Tuesday with Class A Stockton.
"I'm very happy with our pitching, and, obviously, we're deeper with Harden and Foulke coming back," Geren said. "It gives us good options."
However, Geren was unsure whether the A's will expand their pitching staff to 11 to make room when the first is activated.
"We've got to figure all that out," he said. "We have time."
Foulke said the neck stiffness that placed him on the 15-day disabled list, retroactive to April 11, is not a concern.
"I feel great," he said. "I feel better now than when we left for Spring Training. I'm not worried about the injury. I've felt great for over a week now."
Foulke, who signed a one-year deal with the A's just before the opening of Spring Training, recorded a save against the Toronto Blue Jays on April 10, but hasn't been able to get back on the mound since. He has an ERA of 2.57 and had six strikeouts in seven innings.
"I just need to show the team that I'm healthy," he said, "and get activated."
David Kiefer is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.