Walker got the save over the Padres again Sunday, completing five outs while not allowing any baserunners.
Walker picked up the save over the Padres on Saturday, allowing one hit over a scoreless ninth inning.
Walker (9-3) allowed a walk and struck out three over 1.1 scoreless and hitless innings to earn the win Thursday over the Diamondbacks.
Walker picked up his second save of the season in Tuesday's 3-1 win over the White Sox after striking out the side in the ninth inning.
Walker (8-3) got the win over the Athletics on Sunday, allowing an unearned run on two hits and a walk while striking out five over two innings.
Manager Bob Melvin said Friday that Walker will serve as the Giants' closer going forward, Susan Slusser of the San Francisco Chronicle reports.
Walker (6-3) retired both batters he faced and earned the win Sunday over the Twins.
Walker (5-3) walked one and struck out two over 1.2 scoreless and hitless innings to earn the win Friday over the Guardians.
Walker (back) struck out one in a perfect inning to earn a hold in Friday's 10-5 win over the Rockies.
Walker will serve as an opener in Wednesday's game against the Mets, Alex Pavlovic of NBC Sports Bay Area reports.