Cleveland’s Oscar Mercado stole second base twice in the Yankees’ loss on Sunday, with Gary Sanchez behind the plate.

The catcher has thrown out just 19 percent of potential base-stealers this season, well below the league average of 28 percent and a significant drop from his own 30 percent rate last season.

Aaron Boone, though, said Sanchez still has an “elite” arm and noted the Yankees have a number of pitchers not adept at holding runners on.

“Gary is a great thrower,’’ Boone said Sunday. “When he has a decent time from a pitcher, he’s elite. A number of guys on our staff aren’t overly quick to home plate when they don’t slide-step. With most teams, you’d see more attempts against [them]. He does a lot to quiet that.”

Boone’s only critique of Sanchez’s performance was his decision to throw to second on Mercado’s first-inning steal. Sanchez ended up throwing the ball into center field for his 14th error of the season, a new career-high.

“He didn’t have a play, so you just have to eat it,’’ said Boone, who noted most of Sanchez’s errors came early in the year. “That’s a ball he shouldn’t have thrown.’’

On the other side of the ball, Sanchez is having another stellar August, traditionally his best month at the plate. His OPS this month is 1.037, the highest of any month this year and his 1.121 mark in August over his career is also tops.

“Honestly, I don’t know how to explain it,’’ Sanchez said through an interpreter. “The results in August are good. I don’t know why.”

He also said he feels healthy and hopes that bodes well to playing well down the stretch after struggling with a shoulder injury last season.

“It’s hard to know what the future holds, but it will work out if I’m healthy,’’ Sanchez said. “If I’m healthy, good things can happen.”If I’m healthy, things work out the way I want. We’ll see what happens.”

When the Yankees open their series in Oakland on Tuesday, the A’s will reportedly have a new pitcher in their bullpen.

Left-hander A.J. Puk is expected to be called up from Triple-A Las Vegas and could make his MLB debut in the series. Puk, 24, is considered one of Oakland’s top prospects. A first-round pick, sixth overall, in 2016, Puk underwent Tommy John surgery last year and will likely be a starter down the road, but he will be used in relief now as the A’s try to make a postseason push.

The Yankees will begin their Grapefruit Schedule next spring at home in Tampa against the Blue Jays on Feb. 22 and end in Tampa on March 22 against the Tigers.