How Alex Cora Addressed Marcelo Mayer’s Costly Baserunning Error

As a first-week big leaguer, it only was a matter of time before top Red Sox prospect Marcelo Mayer made a mistake on the diamond.

That mental lapse arrived Tuesday night, and it proved to be very costly in yet another frustrating Boston loss.

Mayer was the only Red Sox player to log multiple hits in the visitors’ middle game against the Brewers. The first knock was logged in the fifth inning when the 22-year-old led off the frame with a double in a 0-0 ballgame. Mayer didn’t come around to score, though, as he was thrown out at third base when he attempted to tag up on a Trevor Story flyout to right field.

Boston certainly could have used a run there, as Aroldis Chapman couldn’t preserve a 1-0 lead in the ninth inning, and the Sox went on to lose 5-1 in the 10th. After the game, manager Alex Cora provided a balanced take on Mayer’s baserunning gaffe.

“It”s one of those, we talked about him (Sal Frelick) pre-series. He has a good arm. Obviously, he got behind it. That’s one of those that, yeah, a little bit too aggressive,” Cora told reporters, per MassLive’s Chris Cotillo.

“But we don’t want to take the aggressiveness out of him. There was a dirt ball later on, he was a little hesitant about. He got a great read and he stopped. We talked to him, walked him through what we saw and he’ll let us know what he saw, then keep getting better at it.”

Cora and company surely knew Mayer was going to experience some growing pains upon his promotion. Kristian Campbell, another member of the “big three,” is going through them now after a red-hot start to his MLB career.

But the very early returns on Mayer are positive, and he’ll continue to work through learning experiences as he becomes acclimated to baseball’s top flight.