"[We're] optimistic, and he feels good and wants to get it ramped up as soon as he can," Servais said.
Phelps' full recovery would be a boost to a Mariners bullpen that has struggled of late, allowing 13 runs in the past three games. In the meantime, Servais is hoping someone will step up and perform well in the late innings, when Phelps would typically take the ball.
"We need somebody to step up and finish off an inning and just control the game a little better," said Servais.
• Mariners starter Felix Hernandez, on the 10-day disabled list with right shoulder bursitis, is not throwing yet, according to Servais. He's on anti-inflammatory medication and is undergoing strengthening exercises, along with general conditioning.
• Mitch Haniger (face laceration/small fracture) went 1-for-3 with a homer, two RBIs, two walks and two runs as the designated hitter on the first day of his rehabilitation assignment with Triple-A Tacoma.
Josh Horton is a reporter for MLB.com based in Seattle. This story was not subject to the approval of Major League Baseball or its clubs.