FORT MYERS, Fla. -- Daniel Norris felt lost after his March 3 start against the Yankees, an abbreviated outing that saw him surrender three home runs while recording only five outs.

A day or two later, as Norris walked by Jordan Zimmermann, he half-jokingly said to his teammate, "Fix me." Little did he know, but Zimmermann would do just that.

"I was kind of joking," Norris said. "But he said, 'I know why you're not throwing hard.'"

The veteran Zimmermann identified a flaw in his 25-year-old teammate's delivery that was preventing him from finishing his pitches: Norris wasn't getting out over his front side, leaving his left arm to do all the work. Groin surgery last May had "created a lot of bad habits," according to Norris, who now faces the task of breaking them as he prepares for the 2019 season.

"Before, I didn't have any power because of the groin; after surgery, I was overstriding, overcompensating because I thought I needed to," Norris said. "I was basically building a brick wall and trying to throw over it."

After a few days of side work, Norris put his new-and-improved delivery to the test last Friday, throwing a scoreless inning in a return matchup against the Yankees. On Tuesday, he started against the Red Sox at JetBlue Park, shutting down a lineup of Boston's regulars over three scoreless innings as the Tigers held off a late Red Sox rally for a 4-3 victory.

"It's all about mechanics more than anything else," Tigers manager Ron Gardenhire said. "It's not about arm, injury or anything like that. Once you hurt yourself, your body tells you to back off. Hopefully he's starting to let it go now. I think there's probably going to be more in there once he gets more confident."

Norris limited Boston to four singles and one walk. With a fastball sitting mostly in the 91-92 mph range, he worked out of trouble in each frame, stranding six runners on base, three of them in scoring position.

"The angle and the life on it, 92-93, I can absolutely live with that," said Norris, who wasn't breaking 90 mph early in the spring. "And I'm not even reaching back right now. A few ticks up on velo is huge. Once that becomes muscle memory, then you can start reaching back and be a little more free and easy with it. I'm happy to feel progress but can't wait to keep going."

Norris' fastball wasn't the only pitch to get a bump from the mechanical tweak. Norris had stayed away from his slider of late, noting that the pitch that once registered in the 87-88 mph range had dropped into the 85 mph range. Tuesday, the slider clocked in around 83-85, while Norris felt "it was really sharp."

"It's unreal; it's coming back," Norris said. "Everything we were working on has become more natural. This is the way I'm supposed to throw a baseball."

In Norris' third inning of work, as his pitch count moved into the 40s for the first time this spring, he felt his body beginning to tire. He issued a four-pitch walk with two outs, though he believes the pitches were close and competitive thanks to his mechanics.

"You don't have to rear back and sling it," he said. "I don't have to bear down; it's just trusting it. So even though I was tired, I was still able to make pitches."

Most pitchers would dread seeing J.D. Martinez and Mookie Betts stepping to the plate, but for Norris, it was part of the fun. He and Martinez were teammates in Detroit, while he and Betts go back even further.

"I was happy to see J.D. in there; I wanted to face him," Norris said. "I grew up with Mookie; we played against each other and were on the same team for a couple tournaments. It was good to face him. A couple starts ago, I faced the Yankees and they had a lot of their [regular] guys in there. In the season, you face those guys. You have to battle. If you execute your pitches, you execute your pitches."

Thanks to Zimmermann, Norris is doing that with a whole new confidence.

Worth noting

• Nick Castellanos, who didn't make the trip to Fort Myers to face the Red Sox after getting hit by a pitch on his left hand Sunday, should return to the Tigers' lineup on Thursday. Castellanos will continue to undergo treatment on Wednesday, with no game on the schedule. "He'll be good to go," Gardenhire said. "He'll be in the lineup [Thursday]."

• Right-handed pitcher Drew VerHagen, out since Friday with dead-arm issues, could begin throwing again on Wednesday. "I think he's going to be fine," Gardenhire said when asked if VerHagen would be ready for Opening Day.

• Jordy Mercer launched a two-run homer, his second of the spring, against David Price.

Up next

The Tigers resume their Grapefruit League schedule Thursday at Publix Field at Joker Marchant Stadium against the Red Sox. Left-hander Matthew Boyd is scheduled to start for Detroit, while lefty Eduardo Rodriguez will pitch for Boston. First pitch is scheduled for 1:05 p.m. ET.