PORT ST. LUCIE — One year ago, Jacob deGrom was just trying to make the Mets. And look what happened. He became NL Rookie of the Year.

This spring deGrom is trying to make himself an even better pitcher by developing a curveball. If that comes together, deGrom and the Mets’ rotation could be off the charts with Harvey, deGrom and Zack Wheeler leading the way.

“I think our staff is going to be one of the best in the league with us three,’’ deGrom told The Post on Thursday. “I think we all build off each other and I think we all learn from each other. They’ll be friendly competition.

“One guy goes out there and does a good job, you’ll want to go out there and do a good job,’’ deGrom said. “Along with [Jon] Niese, [Bartolo] Colon and [Dillon] Gee.

“I think it is going to be a lot of fun.’’

Yes, Matt Harvey pitches in a game Friday for the first time since 2013 following Tommy John surgery, but there is a lot more happening with this Mets pitching staff.

Consider that deGrom, who will pitch Saturday, can be so much more relaxed this spring and work on truly honing his craft.

“This spring is so different,’’ deGrom said. “I can really come in here and work on things. Last year when I was over on the big league side, I didn’t throw my curveball one time because I was trying to make the team and prove I could get outs in spring training.

“I was trying to show them what I had and my curveball was a new pitch.’’

So that curve stayed in deGrom’s back pocket.

“You still want to compete and get outs in spring training, but I can do more mechanically this spring,’’ deGrom said.

He began to break out the curveball at the end of the season.

“It’s a great pitch whether it be strike one or a strikeout pitch,’’ deGrom said. “Talking to Gee, Wheeler and all those guys and see how they throw theirs and taking little bits of information from them and trying it in bullpens. Sometimes I throw it at 78 (mph) and that’s a big difference from the slider. It gets the hitter off balance.’’

Harvey is doing the same thing with the curveball.

Spend one day at this Mets camp and you see the camaraderie of the starting staff — especially the three young guns. They had a bullpen session together on the six pack of mounds nearest the clubhouse on Wednesday, along with Steven Matz and Noah Syndergaard.

Three days ago, Harvey, Wheeler and deGrom all put on their new home white uniforms with blue pinstripes for a photo shoot. As they walked out the door, I asked if they were getting their picture taken for the cover of Sports Illustrated.

If they all live up to expectations, that day is not too far off.

DeGrom, 26, is the kind of Tommy John surgery success story Harvey is hoping to become. There already are positive parallels to draw from.

DeGrom had his surgery in 2010.

“Rehab is not fun,’’ he told me. “Matt kept positive the whole time and I think that’s a big part of it.

When you have no setbacks, because my rehab also went smooth, that’s a big part of it. Mine was smooth from Day 1 and so was Matt’s.’’

DeGrom missed all of 2011 and when he came back he had something to prove.

“You start questioning what do they think of me,” he said. “I wanted to go out and prove I could pitch in the big leagues.’’

He did that and much more.

“Matt is different, he’s already proven he can have great success in the major leagues,’’ deGrom said. “The way I’ve seen him throw this spring I feel he’s going to come back just as strong, if not stronger.’’

A staff of young stars is on its way to Citi Field.