TORONTO — There is no doubt now.
The Yankees lost a tough one Sunday, 3-2 to the Blue Jays, who shut out Joe Girardi’s club in the home-run game, 2-0, but the Yankees came out of it knowing they have developed a home-grown ace in Luis Severino.
For all the disappointment Masahiro Tanaka has brought to the rotation, in Severino the Yankees have a young power arm who will lead this rotation for years to come.
After his issues last year in the rotation, this is tremendous growth for the right-hander.
Severino made one critical mistake, surrendering a two-out, two-run home run on a first-pitch slider that came back over the middle of the plate that Justin Smoak deposited into the flight deck in center field of the Rogers Centre that tied the game at 2-2 in the sixth, Smoak’s 14th home run of the season.
The Yankees lost it when Tyler Clippard left a fastball up that Josh Donaldson hit out to lead off the eighth inning on Donaldson’s Bobblehead day.
Brett Gardner marveled at Severino’s development.
“It’s amazing,’’ Gardner told The Post. “A lot of it has to do with fastball command and a lot of it has to do with him just attacking and getting ahead of hitters and his preparation. I think people have to realize he’s just 23 years old, he’s not 28 and has been dragging along for five years.
“He’s a guy that you hope is going to continue to get better, and we’ve seen that over the last two months,’’ Gardner said. “I think he probably throws as hard, if not harder, than any other starter in the game. He’s a guy if he can harness his emotions a little bit and continue to get better with his command, he can be a dominant starter and an ace-type guy at the top of the rotation. I really wish we could have gotten him a win.’’
The Yankees fell short against Marcus Stroman and the Jays bullpen to split the four-game series. Somehow, Toronto won two games despite going 0-for-24 with RISP in the series. Timely home runs can do that for a team.
Following an off-day Monday, the Yankees host the Red Sox for three and then the Orioles come to Yankee Stadium for three.
Tanaka will be on the mound Tuesday, and he needs to get his act together immediately.
When The Post asked pitching coach Larry Rothschild what is the No. 1 thing Tanaka must do in this start, Rothschild offered these intriguing words.
“I think he needs to just worry about one thing and that is the pitch at hand,’’ Rothschild said. “Take the focus off all the other stuff and just make pitches.’’
Don’t get caught up in thinking ahead or lamenting over a previous pitch.
Pitch to the moment.
Rothschild said Severino has mastered so much recently. He made those 11 starts last season and was atrocious, going 0-8 with an 8.50 ERA. This marked his 11th start of this season, and he is 4-2 with a 2.90 ERA.
“The command of the fastball has been the big difference,’’ Rothschild said of Severino, who has allowed four runs over his last four starts, “and to his credit he has really worked at it.’’
The changeup has developed as well as the slider.
But Severino said he wanted that slider to Smoak back.
“I’m a little disappointed in myself because I had the game in hand,’’ Severino said of holding a two-out, 2-0 lead in the sixth. “It’s a tough lineup, they got a lot of power, so I tried to hit the corners and mix in my changeup.’’
Severino then talked about the valuable lesson he has learned from last year to this year.
“I think here you don’t have to be the fastest or the strongest to get outs,’’ Severino said. “I think you have to be the smartest. Last year I was trying to throw my fastball by everybody as hard as I can. You have to be patient and you have to be smart.’’
Sunday was another lesson learned.