TAMPA, Fla. — When pitcher James Kaprielian rolled up to Steinbrenner Field several weeks ago, he had to blink, rub his eyes and do a double take. As he glanced toward left field, there was an incongruous sight on one of the practice diamonds, something he had never seen on a baseball field — an enormous grass mound, 10 feet tall with a 30-yard incline.

It was an early look at the Yankees’ very own Green Monster.

“I’m thinking, ‘What is that?’ ” said Kaprielian, the Yankees’ top draft choice last year. “What is going on?”

When Kaprielian spoke to coaches, he learned that the hill was for conditioning.

“I was like, ‘O.K., this looks like it’s going to be fun,’ ” said Kaprelian, 21, who was not using his fun voice.

The hill, installed during the off-season, is the pet project of Matt Krause, the Yankees’ strength and conditioning coach, who lobbied for it when he was hired away from the Cincinnati Reds after the 2013 season. Krause had a similar hill to work with at the Reds’ training complex in Goodyear, Ariz.