Los Angeles will counter Walker with ace Clayton Kershaw.
Friday's start will mark Walker's first career playoff appearance after 93 regular-season appearances.
The 25-year-old just put together the best season of his career for the Diamondbacks, posting a 3.49 ERA, 1.328 WHIP, and 146 strikeouts across 28 starts. He joined the D-Backs this past winter via trade after spending his first four seasons pitching for the Seattle Mariners.
He pitched particularly well as a visitor in Dodger Stadium this year, holding Los Angeles hitters to a .205 average and .535 OPS during a pair of starts at Chavez Ravine.
While Lovullo has yet to announce who will follow Walker in the D-Backs' NLDS rotation, he's reportedly leaning toward starting left-hander Robbie Ray - who threw 2 1/3 innings of relief in Wednesday's wild-card game - in Game 2 at Dodger Stadium, according to Nick Piecoro of AZCentral.com. Zack Greinke, who started the wild-card game against Colorado, would then be lined up to face the Dodgers in Game 3 at Chase Field.