"Everything went great," McClendon said. "He was clean. No setbacks. We'll continue to move forward."
McClendon said it hasn't been determined yet where Walker will make his next start, though he said it'll be at a warm-weather site. If all goes well, Walker could potentially return to the Mariners, but the manager wasn't committing to that yet.
"We'll see," McClendon said. "I would say he'll throw 85-90 pitches next, and we'll see how he feels after that one."
All-Star right-hander Hisashi Iwakuma hasn't started throwing off a mound yet, but he is scheduled for another long-toss session on flat ground Sunday. If all goes well, he'll throw his first bullpen outing midweek and begin building up his arm strength after missing all of spring with a sprained tendon in his right middle finger.
McClendon said Iwakuma likely will do his Minor League rehab stint in Triple-A once he's ready, which will likely be toward the end of April.
"By the time he's ready, I would think the weather will probably be pretty decent, for the most part," McClendon said. "We will probably see him in Tacoma."
Greg Johns is a reporter for MLB.com. Follow him on Twitter @GregJohnsMLB as well as his Mariners Musings blog. This story was not subject to the approval of Major League Baseball or its clubs.