LAKELAND, Fla. -- Adam Haseley did not always like the thoughts he carried home from the ballpark last season.

He should have been better, he thought to himself. He should have run harder down the line. He should have been more aggressive in an at-bat.

“That would stick with me,” Haseley said Sunday afternoon at Joker Marchant Stadium. “I could have competed better.”

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Haseley, 24, vowed to change, so he worked on his body and mind this offseason. He added 15 pounds of muscle, which might have helped him hit an opposite-field leadoff home run in the first inning of the Phillies’ 10-2 loss to the Tigers during Sunday's Grapefruit League opener. He improved his mindset, which could help him make an extra play in the field or pick up an extra hit at the plate. The combination could help him edge out Roman Quinn, Scott Kingery and possibly Odúbel Herrera for the job opening in center field.

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“I felt like I wanted to compete against myself and try to see how much I could give that day,” Haseley said. “How much better I could get? I think if I can constantly stay on top of that, then I can just make myself better and get our team better. So I'm trying to give it as much effort as I can, as much intensity as I can.”

Physically, Haseley looks different. He finished last season at 190 pounds. He entered this spring at 205 pounds.

“I built my own gym in the garage, the first time I had done that,” he said. “Just put it together.”

Haseley installed a Rogue squat rack at his Orlando home. He drove to Clearwater to borrow dumbbells from the Phillies. He purchased everything else online: medicine balls, bands, etc.

He followed the Phillies’ workout routines on an app.

“I was able to get everything done right there in the garage,” Haseley said. “Sprint in the street. Stuff like that. You couldn't go to a gym. The school that I usually work out at wasn't letting people who weren't getting tested come in. So I was like, 'I don't know what else to do. I'm just going to put one together and see how it goes.'”

Haseley was the eighth overall pick in the 2017 MLB Draft. This is his opportunity to prove he can be an everyday player. He has shown flashes of his potential at times. He played well offensively and defensively in September 2019. He hit .538 (7-for-13) with two doubles and two RBIs in his first five games last season. But then he sprained his left wrist on Aug. 11, 2020, and landed on the injured list. He battled lower back issues.

Haseley batted .227 with three doubles and 11 RBIs over his final 35 games.

“I think he didn’t know how to handle last year,” Phillies manager Joe Girardi said. “You start off good, then he got hurt. It’s not something he’s ever really probably been through, in the sense of a lot of adversity and having to go through what he went through. I think it’s going to make him a better player.”

Haseley is not leaving anything to chance. He changed his bat path, too. He previously hit down on the baseball, but he is trying to keep his bat flatter through the zone this spring.

And Haseley barreled one up on Sunday. A day like that can make a difference.

“I want someone to grab ahold of this,” Girardi said. “It’s one game, but it’s a good start.”