The Philadelphia Phillies and Arizona Diamondbacks enter a pivotal three-games series in Phoenix with fresh starting rotations.

The D-backs, who enter Friday two games behind the New York Mets in the National League wild-card race, will start right-hander Ryne Nelson (7-3, 3.34 ERA) in the opener after implementing a four-man rotation for the final nine regular-season games.

The Phillies adjusted for a different reason. After clinching a postseason berth Tuesday by winning the NL East, they opted to push No. 1 starter Cristopher Sanchez back to Tuesday, when he will pitch on six days' rest and also be in line for the playoff opener.

Philadelphia right-hander Taijuan Walker (5-8, 4.17) will start Friday, with Walker Buehler also expected to pitch multiple innings.

"It'll be a Walker Buehler piggy-back," manager Rob Thomson said.

The D-backs have a three-game home series against the NL West-leading Los Angeles Dodgers next week before concluding the regular season with a three-game road set against another playoff contender, the San Diego Padres.

With an off day next Monday, all four Arizona starters -- Nelson, Zac Gallen, Eduardo Rodriguez and Brandon Pfaadt -- will pitch with at least four days' rest down the stretch.

"The four guys have been leading the charge for us all year long," manager Torey Lovullo said. "They've been throwing the ball well ... some have been throwing the ball exceptionally well.

"We wanted to match up the best way we could against the most critical teams in the most critical times. We felt this was the right thing to do."

Both teams enter on a serious roll.

The Phillies (91-62) are 30-15 since the trade deadline, the best record in baseball. After taking two of three from the Dodgers earlier this week, they won six straight series mainly without ace Zack Wheeler and NL MVP candidate Trea Turner.

Turner, leading the NL with a .305 batting average and 179 hits, has been out since Sept. 7 with a hamstring strain. Thomson said the star shortstop is making "great" progress.

"He just continues to have good days," Thomson said, indicating Turner could return by the end of the regular season.

Phillies DH Kyle Schwarber leads the NL with 53 homers and leads MLB with 128 RBIs. He has played all 153 games.

The D-backs (77-76), who spoiled Pfaadt's nine scoreless innings in a 5-1, 11-inning loss to San Francisco on Wednesday, are 26-18 since the trade deadline, the majors' fifth-best record. They have won seven of their last nine series and split another.

"The Phillies are a great team -- well-managed, and they are loaded with talent," Lovullo said. "We can't let them come in here and muscle us. We have to play our game. I think our game matches up against anybody at any time."

Walker, who spent 2017-19 with Arizona, has given up four runs in each of his last four starts as his ERA has jumped to a season-high 4.17. He yielded four runs in a 5-4 loss to the D-backs last year, his only career appearance against them.

Nelson has gotten stronger as the season has progressed. He has a 2.40 ERA across his last five starts, all quality starts. He is 0-1 with a 4.15 ERA in three starts against the Phillies. Bryce Harper is 4-for-9 with a homer off Nelson.