"It's a learning experience," Castellanos said, per MLB.com, "the highest competition I've played against. The game's a little bit faster. I feel like I'm making really good strides in the outfield. Just trying to find a little bit more consistency at the plate. I'll have one good game where I'll feel great, then I'll have like two games where I can't find it. It's just an adjustment period right now."

Toledo manager Phil Nevin isn't concerned about Castellanos' slow start and he's been happy with his transition to the outfield, which was the more pressing concern at the beginning of the year. Castellanos is considered the Tigers' top prospect by MLB.com.

"The last two weeks, his outfield play has been exceptional," Nevin said. "Gene Roof has done a heckuva lot of things with him. He's been working his tail off. Every day, he's out there. He asks to come out early. He asks to do extra things. I'm very proud of the strides he's made out there."

"It's a process, but every day's getting better," Castellanos said. "I've had some really good reads and made some good plays already this season, so every day I'm just trying to get better."

Castellanos is batting .280 (7 for 25) with two doubles, two RBI and seven strikeouts in six games.

He has no home runs and just one RBI, while adding one run and two doubles. Castellanos, who is considered a top-25 prospect by Baseball America (No. 21) and MLB.com (No. 21), also has six strikeouts and yet to draw a walk.

"They told me I made a good impression. I'm happy about that," he told reporters Tuesday. "They just want me to keep working in the outfield, but they liked the way I looked."

Castellanos will also transition from the infield to left field at Triple-A Toledo this season as the fast riser begins his third professional campaign. He carried a .316 average with 32 doubles and 57 RBI over Class A and Double-A during the 2012 season.