This was supposed to be Noah Syndergaard’s start. Or maybe Steven Matz’s. How about Seth Lugo? Where have you gone, Adam Wilk and Rafael Montero? And welcome back, Matt Harvey — but not until Friday in Milwaukee.

Yes, the Mets needed a starting pitcher on Wednesday afternoon against the Giants. So general manager Sandy Alderson, who crowed in spring training about the Mets’ supposed awesome pitching depth, claimed Tommy Milone off waivers from the Brewers on Monday. Manager Terry Collins sent the veteran lefthander out to the mound on Wednesday against the Giants.

Milone gave the Mets what the injured Syndergaard, Matz and Lugo can’t (and what the Mets chose not to ask for from Montero or Harvey, for different reasons): a decent start.

Milone allowed two runs in five-plus innings. He gave up six hits, walked two and struck out five. The 30-year-old soft-tosser was 1-0 with a 6.43 ERA for the Brewers and is 45-33 lifetime.

Milone also drove in what could have been the winning run with a fourth-inning single and was in line for the victory as the game went to the ninth with the Mets leading 3-2. Unfortunately for Milone and the Mets, Jeurys Familia allowed four runs and the Mets lost, 6-5.

“He threw the ball exactly how we hoped he would,” Collins said. “Changed speeds, threw strikes, mixed ’em up. He’s exactly what we’ve seen and what we’ve heard about.”

advertisement | advertise on newsday

The Mets chose not to start Montero, who was hit hard in his only start; he pitched two-thirds of an inning in the ninth. Harvey, who returned from his three-game suspension on Tuesday, will pitch on Friday in the less-pressurized atmosphere of Milwaukee’s Miller Park.

Wilk, who replaced Harvey on Sunday and was lit up by the Marlins, is a former Met. He was waived on Monday and claimed by the Twins on Wednesday.

So that left it to Milone to become the eighth pitcher to start for the Mets in 33 games. In spring training, Alderson had said: “We are looking for eighth and ninth starters. Most teams are looking for fourth and fifth guys.”

Collins said starter No. 8 will get another outing.

“He’s going to go back out there,” Collins said.

Mets videos

For Milone, it’s a chance to settle in as a Met after a whirlwind three days.

“It’s definitely not ideal,” Milone said. “You have to make do with what you have in front of you. I’ve got to give a lot of credit to [catcher Kevin] Plawecki for the game that he called. It seemed like we were on the same page. It’s a lot easier when you’re not shaking off two of three times every pitch. I’m just happy to be here. The guys were welcoming when I first came in here on Monday. That makes it a lot easier as well.”