DUNEDIN, Fla. -- The glove looks like an old school catcher’s mitt, or an oven mitt that could perfectly pick up a muffin or a cupcake. It does not look like something an infielder would use to field ground balls, since there’s no webbing.

That’s the point of the training glove. It’s why Ramon Santiago used it for years during his playing career to hone his fielding, forcing him to focus on getting in front of the ball and fielding it in the palm of the glove rather than relying on the webbing. It’s why he gave it to Willi Castro when Spring Training began, and why manager Ron Gardenhire is much more upbeat about Castro’s defense than he was five months ago.

“He's done something to put himself in the picture to be a shortstop,” Gardenhire said. “He's a talented kid, and [now] he's made a mechanical adjustment.”

When last season ended, Gardenhire wasn’t sure if Castro would be able to stick as a full-time shortstop or if he would be better served at second base. Even in the small sample size of a September callup, the switch-hitting rookie was playing too many ground balls to the side of his body for Gardenhire’s liking. His footwork also put him in a difficult position for throws at times.

“That was a problem,” Castro said. “I didn't have really good direction to throw to first, and that was making me have a lot of errors.”

Castro was charged with four errors in 28 starts last September, but his metrics showed a greater concern. He registered a negative-3 in Outs Above Average, according to Statcast. His metrics on plays moving laterally were better than on those moving in or back.

“I used to get a lot of errors because the ball would pop out,” Castro said. “This makes me put my glove [at a better angle].”

Both Castro and third baseman Dawel Lugo use pancake gloves in training, but Castro’s glove is a little flatter. They bring the gloves out for their first rounds of ground balls in batting practice, then switch to their regular gloves.

“I take maybe 15-20 a day,” Castro said.

The difference, Gardenhire said, is noticeable.

“I hit him ground balls [Tuesday] at shortstop,” Gardenhire said. “Some of the mechanical things that we talked about, that he was going to have a hard time being a shortstop -- they're gone, all in one winter. With Santiago, his drills, with his flat glove, Castro can't slide through the ball anymore. He has to center the ball. Everything else has just gone away.

“Those are the improvements you just love. I hit him ground balls and I told Santi afterwards, 'He got it. He can do that. He can play shortstop. With those mechanics, he can do that.' And last year I said, 'If he keeps sliding off the ball, it's not going to happen.' But he buried the ball, and it's pretty impressive. It's a really good thing with him.”

That doesn’t mean Castro will be challenging for the starting shortstop job in camp. Niko Goodrum is positioned there, and while the former utility man has missed the last few days with a sore groin, the Tigers are exercising caution with him, since a groin injury ended his 2019 season in late August.

Long term, the Tigers need a shortstop. If either Castro or Goodrum can fill the spot, they would take care of an important part of the Detroit’s rebuild.

“I trust my hands,” Castro said. “I wasn't happy [last September] because I know my hands. I know I can do better. This year is going to be a good year.”