TAMPA, Fla. — The Yankees had one of the best bullpens in baseball in 2018.

In ranking fourth in the majors in ERA (3.38), the group collectively accumulated 753 strikeouts, second-most by a bullpen in major-league history (the Rays, who frequently used relievers as “openers” last year, got a record 754 strikeouts from their pen).

The Yankees’ unit, which ranked first with a 9.7 WAR, per FanGraphs, had four of the majors’ top 17 relievers in strikeouts — Dellin Betances (third with 115), Chad Green (tied for 11th with 94), Aroldis Chapman (tied for 14th with 93) and David Robertson (17th with 91).

By any measure, if the 2019 unit even approaches those numbers, it would be a success. And yet industry expectations are for this year’s bullpen to be even better.

“Scary,” one opposing team talent evaluator said. “They really have five guys with closer stuff. You’re doing good if you have one or two.”

Robertson is gone, having signed a free-agent deal with the Phillies. But Chapman, Betances and Green return, as does Zack Britton, a trade-deadline acquisition a season ago who re-upped as a free agent. He appears healthy for the first time since 2016, when he posted a 0.54 ERA with the Orioles.

The Yankees also signed Adam Ottavino, who struck out 112 in 77 2⁄3 innings in 2018 with the Rockies. Jonathan Holder and Tommy Kahnle are expected to round out the group.

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“I don’t really rate them because it’s going to come down to performance at the end,” said Larry Rothschild, who is entering his ninth season as Yankees pitching coach and has overseen plenty of good bullpens. “They have the potential to be really, really good, and that’s a nice position to be in going into the season.”

Chapman is the closer, but preceding him could be any combination of arms.

“I don’t think we’re at that point right now,” Rothschild said of where pitchers will slot in the mid-to-late innings. “I think as we’ll go, we’ll see where guys are in their health and all that, but I think there’s some interchangeable parts there.”

Green sees that as a positive for the corps.

“It just gives us a lot of depth,” he said. “Especially to give guys a day [off] here and there is huge. Obviously, it’s a long season, so if you need to give a Chapman a day, Britton can close, Dellin can close. Pretty much we have at least four closers down there, so it’s going to be fun to watch for sure.”

Green wasn’t counting himself, but most scouts see him as closer material, giving the Yankees five capable ninth-inning options.

Green said he learned from Britton during the two months the lefthander was with the club last season, primarily lessons about “preparation” and his ability to “bounce back.”

Even before Ottavino signed with the Yankees, Green paid close attention to him in the postseason.

“His slider, his two-seamer — I think it pairs really well,” Green said. “And I think he’s big into pitch analytics and tunneling pitches [throwing two different pitches along the same trajectory as to better fool the batter] and stuff like that. So I think especially for me, just being able to take something from him I think would be huge.”

Rothschild, starting his 45th season in professional baseball, is well aware of the bullpen’s potential, but he’s been around long enough to avoid the hype.

“You have to like them going in, but the biggest thing is to stay healthy,” said Rothschild, the bullpen coach for the 1990 Reds, who featured “The Nasty Boys” (Rob Dibble, Randy Myers and Norm Charlton). “Keep them healthy through the spring and get them ready to start the season.”