With 10 days of Cactus League play remaining, manager Lloyd McClendon remains noncommittal on Walker's competition with southpaw Roenis Elias for the final spot in Seattle's rotation.
"He was OK," McClendon deadpanned after Walker's latest dominant outing, in which he struck out six and worked through six innings on 82 pitches.
Does the manager still need to see more from the young right-hander, who has allowed just six hits and three walks with 19 strikeouts over 18 innings in his five starts.
"Just stay consistent," McClendon said. "Keep pitching well. He threw up a lot of zeroes and pitched well. He fatigued a little in the sixth, but I thought he threw the ball extremely well."
Walker faced just one batter over the minimum in his six frames, thanks to a pair of double-play grounders. He gave up an infield single in the second, but erased that with a 6-4-3 twin killing. Then in the sixth, a one-out walk to Cubs pitcher Travis Wood and a single by Arismendy Alcantara had the youngster in his first hot water.
But Walker threw a changeup to Cubs leadoff man Dexter Fowler, who laced a ground ball up the middle that second baseman Robinson Cano fielded slickly and turned into another double play to cap Walker's night.
Catcher Mike Zunino called Walker's stuff "unbelievable" and said his fastball location and offspeed pitches keep getting better as he goes. Walker was consistently hitting 94-96 mph with his fastball, and blew away Miguel Montero with a 97-mph heater as he struck out the side in the fourth.
"It just comes out so easy that it's tough to time up," Zunino said. "He's got late explosion [and it] sort of takes off."
Walker said everything felt smooth in his longest outing of the spring. And he knows exactly what needs to be done going forward.
"I just need to keep it right there, keep going out there and attacking," he said. "Just going right after hitters, throwing strikes."
Elias gets his fifth start of the spring Thursday against the Brewers in Maryvale on a split-squad day. The 26-year-old lefty has posted a 3.86 ERA in his first four outings and was a 10-game winner last year as a rookie, but obviously has his hands full in keeping up with Walker.