Walker threw 40 pitches in his second time up on the mound since he was shut down in mid-April with stiffness in his right shoulder during a rehab stint with Triple-A Tacoma. Paxton threw 52 pitches in his third bullpen session since straining his left lat muscle on April 8 in Anaheim in his second start of the year.
Both youngsters said Wednesday's work went well and that they would accompany the team on its coming road trip to continue working. Walker has yet to throw in a Major League game this year after his shoulder began flaring up at the start of Spring Training, but he sees light at the end of the tunnel.
"Oh yeah," said the 21-year-old, who is rated the No. 6 prospect in baseball and No. 1 in the Mariners' system by MLB.com. "I think a couple weeks maybe, if I don't have any setbacks. So we'll just see how I respond tomorrow, and we'll go from there."
Paxton is a little ahead of Walker's schedule, as he was scheduled to throw a simulated game Saturday in Minnesota. He could either throw one more sim game after that or go immediately out on a Minor League rehab assignment, with a potential return around the end of May if all goes well.
The 25-year-old lefty ramped things up a notch on Wednesday, with good results.
"[It was] as intense as you can get in a bullpen," he said. "I kind of have trouble getting to that game intensity in a bullpen, but still I was throwing everything and throwing it hard, so it was feeling good."
Manager Lloyd McClendon indicated Paxton indeed was not far from heading to a Minor League rehab stint, which is the last step before rejoining the club. The youngster was 2-0 with a 2.25 ERA in his first two starts and is 5-0 with a 1.75 ERA in six starts since his Major League debut last September.
"I don't have an exact schedule; I can't tell you that," McClendon said. "But I can tell you he's close. If all goes well and he continues to progress, then yeah, he's close."
Greg Johns is a reporter for MLB.com. Follow him on Twitter @GregJohnsMLB as well as his Mariners Musings blog. Adam Lewis is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.