Jacob Turner will likely return to the Nationals’ starting rotation soon. (David Zalubowski/AP)

Jacob Turner was dominant over four scoreless innings out of the bullpen at Nationals Park Wednesday night. He entered with the game tied at 1 in the sixth inning and held the Diamondbacks to two hits. He didn’t walk a batter. He needed just 47 pitches to record the 12 outs. His effort allowed Ryan Zimmerman’s go-ahead RBI double in the sixth inning to stand as the difference in a 2-1 victory.

It was the kind of performance the beleaguered Nationals bullpen — shorthanded this week — needed. But don’t expect Turner, 25, to bolster the relief corps much longer. Manager Dusty Baker doesn’t think of Turner as a swingman. He’s a starter in his eyes, and explained that Turner only relieved Gio Gonzalez on Wednesday out of necessity. He had hoped to avoid using him so Turner could take Joe Ross’s place in the rotation this weekend.

“He was just starting a game in the middle of the game,” Baker said Thursday morning. “In my mind, he was a starter. His pitch count wasn’t high. He was capable of going a whole lot more innings the way he was performing and that’s why we stayed with him. He was throwing the ball well and he saved the bullpen that.”

The Nationals will turn to A.J. Cole as their fifth starter on Saturday against the Phillies because Turner was needed on Wednesday, but Baker indicated the plan is for Turner eventually to claim that spot. Baker, however, said he’ll wait to see how Cole pitches before the club makes a final determination.

Turner, a 2009 first-round pick without any options remaining, joined the Nationals on a minor league deal with an invitation to spring training. He posted a 2.61 ERA in three starts for Class AAA Syracuse before he was called up to start against the Colorado Rockies at Coors Field, baseball’s well-known hitters haven. The assignment was daunting, but he allowed just three runs in six innings before going to the bullpen.

Turner then made one relief appearance before Wednesday’s crucial outing, which was necessary because Cole was serving a suspension that carried over from last season and Shawn Kelley was sick.

“He wasn’t any different than he was in Colorado when he started,” Baker said. “He wasn’t any different at all. He was the same guy that impressed us in spring training.”

● Adam Eaton appeared in the Nationals clubhouse, brace on his left knee and crutches in tow. The outfielder said surgery on his torn ACL and meniscus hasn’t been scheduled. Eaton also suffered a high-ankle sprain beating out an infield hit against the Mets last Friday. He is expected to miss the remainder of the season.

● Koda Glover threw long toss in the outfield on Thursday morning, which is a positive sign for the right-hander. He is on the 10-day disabled list with a left hip impingement and can come off Saturday. But the Nationals may elect to wait until Sunday if Cole starts Saturday, because Cole is the likely candidate to be removed from the roster to make room for Glover.

A.J. Pollock CF
Chris Owings RF
Paul Goldschmidt 1B
Jake Lamb 3B
Chris Herrmann LF
Chris Ianetta C
Daniel Descalso 2B
Nick Ahmed SS
Braden Shipley RHP

Trea Turner SS
Jayson Werth LF
Bryce Harper RF
Ryan Zimmerman 1B
Daniel Murphy 2B
Anthony Rendon 3B
Michael A. Taylor CF
Jose Lobaton C
Max Scherzer RHP