As much as the Yankees believe in their rotation, they entered the regular season confident they were uniquely prepared to deal with the lack of buildup in their starting pitchers. 

And that wasn’t just because of their faith in the back end of the bullpen, but also due to the presence of Michael King and Clarke Schmidt. 

It’s one of the reasons the Yankees decided to open the season with 16 pitchers and just a dozen position players — essentially using both extra roster spots on pitching depth. 

Both King and Schmidt have pitched well already for multiple innings over the first series of the season. 

How long the Yankees have the luxury of having the pair of right-handers in the pen is up for debate. 

“We’ll see,’’ Aaron Boone said of the bullpen’s makeup before the Yankees started a four-game series against the Blue Jays on Monday night at the Stadium. 

“You can sit there and do the math of who will be in the pen when we have eight guys down there,’’ the manager said. “But we’re still a few weeks away from that and things always can change.” 

For now, Schmidt and King “no doubt” give the Yankees added flexibility due to their histories as starting pitchers. “Their first outings were encouraging.” 

The same can be said of the bullpen overall, which was leaned on heavily during the Boston series, allowing just two earned runs in 18 ²/₃ innings for a 0.96 ERA, while striking out 19 batters. 

Aroldis Chapman, Jonathan Loaisiga, Chad Green, Lucas Luetge, Wandy Peralta and newly arrived Miguel Castro and Ron Marinaccio had combined for 12 ¹/₃ scoreless innings entering Monday night. 

The only two earned runs allowed have been by Schmidt — who allowed a solo homer Sunday night, which was the lone base runner he allowed over 2 ²/₃ innings — and Clay Holmes, who has given up a run in 1 ²/₃ innings this season. 

“We obviously can’t use eight relievers a night, but for now, those guys are doing everything we could ask for,’’ Boone said. “They’re all able to do different things, which gives us more options.” 

Schmidt, who the organization still views as a starter, but some scouts believe is better suited to the bullpen due in part to his injury history, said he’s comfortable pitching in the role he’s currently in. 

“I know what the team expects of me and I’d love to be in the rotation at some point this year, but right now, this is where they need me and I know they’re putting me in good position to succeed,’’ Schmidt said. “We’ve seen a lot of guys pitch in a lot of different roles the last couple years, so you want to be a part of that mix. As long as I’m healthy, I think I can help wherever they put me.” 

Entering Monday night, only the Diamondbacks had needed more innings out of the bullpen (23 innings) and the Yankees’ strand-rate of 88.2 percent was third in the American League, trailing Tampa Bay and Minnesota. 

“Hopefully we’re not running them out there like this for too long,’’ Boone said. “We might like to add a position player at some point, but for now, this is working for us.”