Livan Hernandez gave up eight runs (four earned) over 3 2/3 innings on Thursday against the Mets. (AP)

PORT ST. LUCIE, Fla. -- Battling injuries all spring, the Mets have been mostly healed for a few days now. But health is one thing. Production is another.

David Wright began producing in a big way Thursday in an 9-1 victory over the Astros, hitting a grand slam off Livan Hernandez in Wright's third game back from injury. Jason Bay drove in two runs, and Daniel Murphy and Josh Thole each finished with two hits to lead the offensive attack.

With the Mets already ahead, 4-1, in the fourth, Wright launched his first home run of the spring just over the left-field wall, plating Thole, Mike Pelfrey and Ruben Tejada.

"Livan, he can be a nightmare," Wright said. "He just goes and he exploits your weakness. I kind of got lucky and ran into one. We put together a good inning, though. That's the key to a good offense, is to keep that line moving and let the next guy do the damage."

Spring Training
• Spring Training schedule

Wright is scheduled to play again Friday, appearing in a day game after a night game for the first time this spring.

Given the cushion provided by the Mets offense, Pelfrey submitted his best and longest start of the spring, limiting the Astros to one run over 6 1/3 innings. Pelfrey struck out three and walked none, allowing three hits.

Hernandez did not make it out of the fourth inning, though only four of the eight runs against him were earned. Still, the right-hander's Grapefruit League ERA rose from 4.38 to 5.63.

The Astros did receive two innings of shutout relief from Wilton Lopez, who struck out one and allowed one hit.

Up next:On deck for the Astros is a split-squad day on Friday. Some of the Astros will host the Braves at 5:05 p.m. CT, as right-hander Bud Norris will make his first start since experiencing tightness in his triceps. The rest of the team will travel to Lake Buena Vista, Fla., to take on the other half of Atlanta's squad at 6:05 p.m. CT. Kyle Weiland will be on the mound for the Astros, making his fourth start of the spring.