Then two weeks ago, prized prospect Gleyber Torres was called up to play second base every day. The move shifted Walker to a platoon at first base but hardly fazed the veteran.
On Saturday, he delivered the game-winning single in the 11th inning. On Sunday, Walker and the Yankees attempt to get another series victory when they host the Oakland Athletics in the rubber match of a three-game set at Yankee Stadium.
"He's a pro," Yankees manager Aaron Boone said after Walker's fourth career walk-off hit made it 18 wins in 21 games. "He's proven who he is throughout his career and that's a guy that can hit."
Walker went 2-for-5 and is hitting .360 with eight walks in his last nine games while seemingly contributing something to most of New York's late-inning comebacks in recent weeks. Before this hot stretch, Walker batted .163 in his first 21 games after the Yankees signed him March 12.
"As a guy who's played this game a long time, you know when it's starting to come and when it's starting to feel good," Walker said. "In Anaheim, I had a good series of hitting balls on the barrel and you just try to run with that and throw together good at-bats."
Walker's surge is coming at a time when first baseman Greg Bird is rehabbing from right ankle surgery and could return in the upcoming weeks.
"He's a guy who can fit in anywhere," Yankees right fielder Aaron Judge said of Walker.
Since Walker was able to deliver another key contribution, the Yankees can win their seventh straight series before heading out on an eight-game road trip through Washington, Kansas City and Texas.
Oakland will be looking to rebound after wasting numerous opportunities. After hitting four homers and getting 14 hits in Friday's 10-5 win, the A's drew eight walks but were 2-for-11 with runners in scoring position and didn't get a hit after the fifth inning.
Khris Davis homered for the second straight game and has homered in his last three games at Yankee Stadium, but the A's have dropped four of five since last weekend's three-game sweep of Baltimore.
"Most of our damage came early on. We got six hits," Oakland manager Bob Melvin said. "When you get later on in the game like that, you feel like one hit's gonna win it and they end up getting the big hit in the last inning."
Although the Athletics have 16 runs in the last two games, they are hitting .224 in the last five contests. Among those slumping are Matt Chapman (3-for-41 in his last 11 games) and Matt Olson (5-for-31 in his last eight games).
New York's Luis Severino (5-1, 2.21 ERA) will make his second attempt at getting a sixth win. He took a no-decision in Tuesday's 3-2 victory over the Boston Red Sox when he allowed two runs and six hits in six-plus innings.
Severino struck out 11, but one was a wild pitch on a strikeout in the fifth inning that ultimately led to 17 extra pitches, including an RBI single to Mookie Betts.
Severino is 3-0 with a 1.54 ERA in his last five starts and has 21 strikeouts in his last two outings. If he can get at least 10 strikeouts Sunday, he will become the fifth Yankee to post three straight games with double-digit strikeouts.
On Tuesday, nine of his strikeouts occurred on sliders. In the 10-strikeout game in Houston, six strikeouts occurred on four-seam fastballs.
Severino does not own a decision against the Athletics but has a 4.50 ERA in two starts against them.
Brett Anderson will make the third start of his second stint with Oakland. So far, he is 0-1 with an 8.68 ERA after allowing nine runs (seven earned) and 10 hits in three innings of a 16-2 loss to the Houston Astros.
The start against the Astros occurred after he pitched 6 1/3 scoreless innings during a no-decision at Seattle in his season debut.
Anderson is 0-5 with a 6.81 ERA in seven career starts against the Yankees. He last faced them in his final start for the Toronto Blue Jays on Oct. 1, pitching five scoreless innings in the final game of the 2017 regular season.