PHOENIX - The Mets' newest infield alignment lasted all of two innings. And now, a roster that has long been stretched past its breaking point faces the prospect of enduring through another loss of manpower.

Fresh from his latest move from second base to third base, Daniel Murphy left before the third inning of Thursday night's 6-2 win over the Diamondbacks with what the team called tightness in his left quadriceps.

Already riddled with injuries, the Mets can ill afford another extended absence, particularly from one of the most productive bats in an underwhelming offense, which was enough in this game to help ace Matt Harvey earn his first win in nearly a month.

Mets outfielder John Mayberry Jr., who entered play hitting .137, took advantage of his spot start against lefty Robbie Ray. Mayberry finished with a career-high four hits, including a two-run homer in the ninth that provided an important cushion.

Through five innings, the Mets had little to show but a string of blown chances. But they seized control with a three-run sixth, powered mostly by Kevin Plawecki's two-run double high off the centerfield fence. Plawecki scored after a single by Harvey and a sacrifice fly by Ruben Tejada, turning a 1-0 deficit into a 3-1 lead.

In earning his first victory since May 8, Harvey (6-3) allowed two runs and six hits in seven innings. He struck out nine and walked one, limiting the damage to solo homers by Jarrod Saltalamacchia and Paul Goldschmidt.

Jeurys Familia recorded the final five outs for his 16th save.

The Mets won for only the second time in their last 11 road games, thought it might have come at a steep price.

Murphy, who doubled in his first at-bat, has reached base safely in 14 straight games. During that span, he's hitting .412.

Before the game, manager Terry Collins shifted Murphy to third base to supplant Tejada, who moved to second.The Mets stopped short of a full reshuffling, though. Range-challenged shortstop Wilmer Flores remains entrenched, partly because Collins believes moving him would create controversy and distraction.

"We're trying to play baseball here and stay off the back pages," Collins said.

Still, Murphy's best position is third base, which conceals his range issues. And Tejada is a shortstop, making the middle infield a more natural fit. Those moves alone bolstered the Mets' infield defense.

"I think it makes us a better ballclub immediately," said Murphy, who discussed the idea with Collins and third- base coach Tim Teufel. "So we're going to do it."

Collins said he has been weighing the shift for more than a week, though he took action once it became clear that David Wright's back injury will keep him out for several more weeks.

But by the third, Murphy had left the game. He was replaced by Eric Campbell, who extended his hitless streak to 27 at-bats.

Dillon Gee, who for now is expected to make his next start in the Mets' six-man rotation, has been the only Mets to come off the disabled list this season.

Catcher Travis d'Arnaud and second baseman Dilson Herrera continued to move closer. Though both played in rehab games Thursday night with Class A Port St. Lucie, neither is expected back within the coming week.

A dozen players still are on the Mets' disabled list. They can hardly afford to add any more.