Paxton is 3-3, with a 3.70 in 10 games this season after opening the year as the Mariners' No. 2 starter.
"I've been preparing myself, thinking about it, visualizing," Paxton said. "I think I'm ready for it and I'm excited."
If Paxton gets through three innings on less than 45 pitches, he'll go to the bullpen to throw until he reaches that pitch count. Manager Lloyd McClendon said Paxton will need at least two rehab starts, and more likely three, before he rejoins the team in early September.
"Whatever they decide," Paxton said. "This first one, I just want to go out there and be healthy and have no pain. I'll try to throw all my pitches, be effective, go after hitters, get ahead of them. Then the second one is when you really start to fire it up and get everything going."
• Veteran lefty reliever Joe Beimel, who went on the disabled list Friday with shoulder fatigue, said he'll take a few days off and then begin playing catch again, with the hope of returning as soon as his 15 days are up.
Beimel had given up five home runs in his last 1 2/3 innings before finally acknowledging his shoulder wasn't OK.
"I'm kind of stubborn and hard-headed," he said. "I don't really know when to back off and shut it down. I just figured I'd get through it, like I have a million times before, and it just didn't work. We're all competitors and you want to go out and pitch and do your job every day."
• Robinson Cano had 29 doubles going into Saturday's game. He's one shy of becoming the sixth player in MLB history with 30 doubles in 11 straight seasons. Only Stan Musial and Honus Wagner (13 each) and Tris Speaker (12) have had more, with Joe Medwick and Joe Delahanty at 11. He'll become the first player in MLB history to record 11 straight 30-double seasons to open a career, a mark he currently shares with Albert Pujols with 10.
Greg Johns is a reporter for MLB.com. Follow him on Twitter @GregJohnsMLB, read his Mariners Musings blog, and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.