The New York Mets' bullpen struggled in a 6-3 loss to the Houston Astros on Sunday, undoing a promising start by rookie Zac Thornton and leading to a series defeat. The loss concluded a six-game homestand at Citi Field for the Mets, who dropped their fourth game in five and their third consecutive series.

Thornton pitched five innings, allowing two earned runs on six hits while striking out five and walking none. His performance, which lowered his ERA to 2.93 across his first 11 MLB starts, kept the Mets in contention. The left-hander flashed potential, allowing only one extra-base hit after surrendering a leadoff home run to Jeremy Peña.

Despite Thornton's efforts, the Mets' relief corps faltered. Jonathan Pintaro allowed a two-run homer in the sixth inning that gave the Astros a 4-3 lead. In the seventh, Jefry Yan issued a walk and allowed a single before a hit batter loaded the bases. While Yan induced a ground ball, an errant throw from first baseman Jared Young resulted in an error, allowing another run to score and extend Houston's lead to 6-3.

Earlier in the game, the Mets had taken a brief lead in the first inning. Francisco Lindor and Juan Soto hit back-to-back home runs to answer Peña's leadoff blast. However, the Mets managed only two more hits for the remainder of the game, struggling to generate offense against the Astros.

The Mets' bullpen had been a relative strength since the All-Star break, posting the third-lowest ERA in the majors at 2.64. Sunday's outing marked a rare clunker for the group. Young's throwing error in the seventh inning proved particularly costly, capping a difficult afternoon for the team.