The Yankees took 28 players north with them when they left spring training last week.

By Tuesday, when Nestor Cortes Jr. started to mark one full turn through the rotation, 27 of them had made an appearance in at least one game. JP Sears was the last one left, and adding to the left-hander’s long wait was the fact that his season debut would double as his MLB debut.

Sears’ parents and girlfriend had also been in The Bronx since Opening Day, wanting to stay as long as it would take to make sure they would be in attendance for his first game pitching in the majors.

Finally, in the ninth inning of Wednesday’s 6-4 loss to the Blue Jays, Sears got the call and made the most of it, retiring Santiago Espinal, George Springer and Bo Bichette in order on eight pitches.

“Not too many nerves, more so just a lot of excitement, floating feeling … just super ready to get out there and get after it,” Sears said Thursday in the Yankees clubhouse.

The 26-year-old Sears had not pitched in a game since April 4, a Grapefruit League exhibition, after which manager Aaron Boone informed him he was going to make the team.

From there, the waiting game began.

“Just a little anxious,” Sears said. “Obviously ready to go every night whenever the game started, but just being patient and waiting for my opportunity and take advantage of it how I can.”

Sears’ debut included a strikeout of Springer, with the ball from that at-bat headed to his dad’s office, at least until he has his own home.

“That’ll be one I remember for a long time,” he said.

The Yankees added Sears to their 40-man roster in November, boosting his chances of appearing in the big leagues this season. The former 11th-round pick of the Mariners in 2017 — he came to the Yankees later that year in exchange for Nick Rumbelow — opened eyes last season, when he posted a 3.46 ERA between Double-A Somerset and Triple-A Scranton/Wilkes-Barre.

Sears has been mostly a starter throughout his career and was building up as such in spring training. But with the Yankees carrying 16 pitchers on their 28-man roster for the first month of the season to protect their arms after a short spring training, Sears made the team as a long reliever — his one-inning debut notwithstanding.

“In a perfect world, at some point here we’ll get him in and let him run,” Boone said. “We’ve just been in these high-leverage games each and every night where we haven’t had a lot of chances for our length guys to just roll.

“I think everyone got a little peek at why we’re excited about him.”

The Yankees will have to cut down their roster to 13 pitchers by May 1, meaning Sears’ first stay in The Bronx may be limited, barring injuries elsewhere in the bullpen. But he at least got his first MLB game under his belt — a successful one at that — with his parents and girlfriend in attendance before they went home to South Carolina on Thursday.

“It was the last night my girlfriend was able to be here before she had to go to work today, so that was great,” Sears said. “And then obviously it’s just better to have a debut in Yankee Stadium.”

Home for Sears and his parents is Sumter, South Carolina, which is also the hometown of fellow Yankees left-hander Jordan Montgomery, who was happy to see Sears get his shot Wednesday night.

“It was awesome, I was ready for him to get out there,” said Montgomery, who is three years older than Sears. “I’ve known JP for a while. We work with the same pitching coach back home. He went to the private school, I went to the public school. It’s a small baseball town, so you kind of know everyone that’s good.”