SAN FRANCISCO — The Giants haven’t been able to go through any handshake lines in Blake Snell’s starts. They continue to have huge issues when others try to fill in for him, too.

The first bullpen game under Bob Melvin went off the rails in the middle innings, as the Giants lost 8-2 to the New York Mets on Wednesday at Oracle Park, and fell short in their latest attempt to win a third consecutive game.

The Snell slot in the rotation has come up five times, with the reigning Cy Young winner making three starts and depth arms trying to fill in twice. The Giants have lost all five games, getting outscored 55-12.

The Giants were hopeful they could finally turn things around Wednesday, but Snell was scratched in the morning with an adductor strain and will miss at least two weeks after being placed on the 15-day IL. That kept him from going up against former Giant Sean Manaea, who helped clear the way for offseason rotation additions when he opted out of his contract.

Manaea has pitched well in his first season in New York and he struck out the side in the first. He ended up going 4 2/3 shutout innings, although four walks ran up his pitch count to the point that he wasn’t around long enough to qualify for the win.

The Giants had two walks and loaded the bases with no outs in the second inning, but Thairo Estrada and Tyler Fitzgerald popped up and Nick Ahmed flew out to center. They drew two more walks in the third, but Austin Slater was picked off second base, halting their momentum. From there, it was all Mets.