Jason Bay played his first game in the majors since last summer last night. Is it a coincidence that the horribly struggling Mets, who had lost nine of their last 10, erupted for their highest-scoring game and most-emphatic win of the season?

Bay tried to downplay his return and manage expectations, but for one night, his return sparked the Mets. He doubled and scored two runs, including one on a four-base error, to help lift the Mets to a rare 9-1 rout of Houston last night at Citi Field.

“Maybe with me being here, it lets other guys settle into their roles,” said Bay, who hit fifth in the lineup, sandwiched between Carlos Beltran and Ike Davis. “Hopefully there will be a trickle-down effect to that. But I’m not trying to step in here and take over this team.

“I think I’m a big part of this team,” he said. “Things haven’t been great, but I’m definitely not trying to come in here and shoulder the load.”

It has been a tough go for Bay in Flushing, since he signed a four-year, $66 million contract before last season. He suffered a concussion on July 23 when he crashed into the outfield wall at Dodger Stadium, playing just two more games before going on the 15-day disabled list and not playing again. He ended his shortened season with a .259 average, just six home runs and 47 RBIs.

“I feel like I’m better than that guy,” said the 32-year-old Bay, who strained his rib cage two days before the Mets broke spring training camp, going back on the disabled list. “Even before the concussion, I wasn’t playing all that great.”

But Bay made an impact in his return. He dropped a double down the right field line in the third inning, advancing on a wild pitch and scoring on Davis’ sacrifice fly. When he hit a fly ball to right in the eighth, Hunter Pence dropped it and Bay legged all the way around to score.

“He’s a huge factor,” manager Terry Collins said. “His presence in the clubhouse, his presence on the field, we’re getting another guy who is a star. He’s a huge addition to any lineup and right now we need it here.”