"It definitely gives me a lot of confidence where I can go out there and not really think about it," Walker said after throwing 45 pitches to teammate Luis Sardinas in the practice-game setting. "The last couple days have been really good."
Walker will have another lighter throwing session on Friday, and if all feels right, he will make a Minor League rehab start on Monday. The Mariners haven't settled that yet, but Triple-A Tacoma plays at home against Albuquerque that night, so that would seem the likely destination.
That opens the potential of Walker rejoining the Mariners as early as Aug. 6 against the Angels, but manager Scott Servais cautioned against assuming anything at this point.
"We'll see how he does," Servais said. "I don't want to say it's just one rehab and then he's back. I want to make sure everybody that sees him pitch -- trainers, coaches at whatever affiliate he's at -- feels really good about where he's at. It's really important. There's a big enough window left in our season that he can certainly impact us, so we really need him healthy and ready to go."
Walker said his foot felt fine throughout his outing Wednesday, and he tested it by digging hard to fire his best fastballs.
"I was getting in there with high fastballs and pitching inside," Walker said. "To pitch inside, you really have to drive the ball through to a lefty, so I was getting it in there. My fastball command is a little off still, but my breaking ball was good, slider was good. I had some good changeups, but my fastball command has to be better."
• Nelson Cruz wasn't in Wednesday's starting lineup because Servais wanted to give him a day after he fouled another ball off his left leg in Tuesday's 7-4 win over the Pirates and was removed in the seventh inning. Servais said the 36-year-old slugger will be back in against the Cubs on Friday.
• Servais said shortstop Ketel Marte, who is on the 15-day DL with mononucleosis, is starting to feel better and regaining some of the weight he's lost since coming down with the illness last week.
• Dillon Moyer, the 25-year-old son of Jamie Moyer, signed a Minor League deal with the Mariners and was assigned to Class A Short-Season Everett. Moyer was recently released by the Dodgers, who initially drafted him in the 38th round in 2013 as an infielder out of UC San Diego. He converted to pitching last year and was 2-0 with a 6.55 ERA in 11 innings over nine relief outings over the past two seasons in Rookie-level and Class A Advanced ball.