Walker (foot) threw a three-inning simulated game Wednesday, Bob Dutton of the Tacoma News Tribune reports.
Following Wednesday's session, Walker said he felt no pain in his foot after throwing at max effort and fielding bunts. The preliminary plan is for Walker to throw a bullpen session Friday, and if all goes well, he could begin a rehab stint at Triple-A Tacoma as soon as Sunday or Monday. At this point, the right-hander is on track to return sometime in early August.