LAKELAND, Fla. -- Ron Gardenhire is turning to Jordan Zimmermann for a second consecutive Opening Day start. When the Tigers manager made the official announcement Sunday morning, he confirmed what had been expected ever since the Spring Training pitching schedule was set.

Pitching coach Rick Anderson, Gardenhire said, “had set that up a long time ago. We talked about it this winter. I told him, ‘You’re the pitching coach. You tell me who you want, and I’ll go with you.’ That was it. He thinks that he’s the veteran guy, been around and done it, handles it the best. We’ll be fine with that.”

Zimmermann gets a repeat engagement on Opening Day, but the atmosphere will be different when he takes the mound Thursday in Toronto. So, too, he believes, is his pitching. An assignment that was seemingly set before Spring Training began serves as a culmination of a full camp of work by the right-hander on transforming his game.

With core muscle surgery behind him and his neck and back issues subsided, Zimmermann spent Spring Training focused on his pitches for the first time in years, maybe since his first camp as a Tiger in 2016. At age 32, he could focus on maturing as a pitcher.

“I used to be, I guess, a power pitcher -- fastball, slider and occasional curveball,” he said a month ago. “Now over the years I’ve had to learn I don’t have the mid-90s fastball anymore. I have to get a little more creative. As you get older, you supposedly get wiser, so I’m going with that route. …

“I’m a realist. What I see is what I have. So I’ve accepted it. There’s a lot of guys that used to be power pitchers that aren’t anymore, and they’re doing just fine still. The game’s about adjustments. You make a few adjustments along the way and keep on pitching.”

The transition began last season. His four-seam fastball and sinker usage, which topped out at 70 percent of his pitches in 2014 according to FanGraphs, fell under 50 percent for the first time in '18, down to 45.1 percent. His slider, which comprised just under a quarter of his pitches in '17 according to Statcast, jumped to a third last year. His curveball, a distant third pitch for years, became more effective -- and in turn, more important.

“I’ve gotta keep throwing it, throwing more,” Zimmermann said after his final Spring Training tuneup Saturday. “I’ve gotta throw more sliders, more curveballs, and probably less fastballs. When I was with Washington, I always had a good fastball, and I could be able to rely on that whenever I was in trouble. And now that’s gone down a little bit. Hitters are hitting less off my slider, so I’m going to have to throw a few more of them, a few more curveballs and a few less fastballs, kind of almost pitch backwards a little more. Just gotta get outs.”

At his most effective stretch last year, that’s what he was doing. For six starts from April 30 until early July, with an injury stint in between, he allowed just 21 hits over 37 innings with five walks, 34 strikeouts, a .163 batting average allowed and a 1.22 ERA.

He quieted the Blue Jays at Rogers Centre on Canada Day with seven innings of one-run ball and six strikeouts, then topped that five days later with eight innings of one-run ball and 11 strikeouts against Texas. He was an out away from seven more innings of one-run ball at Tampa Bay to close out the first half of his season when C.J. Cron’s three-run homer spoiled it.

Zimmermann was 4-0 with a 3.51 ERA before that start. He went 3-8 with a 5.28 ERA the rest of the way, allowing 91 hits -- 22 of them homers -- over his final 75 innings. Part of the issue was injury, especially the core muscle issue. But he also lost the feel for the curveball, and all but abandoned it.

Zimmermann clearly doesn’t want that to happen again. When Avisail Garcia fouled off one slider after another to extend his first-inning at-bat to a 10th pitch Saturday, Zimmermann turned to the curveball to finish him off. An inning later, Zimmermann used a retinkered changeup -- historically little more than a show-me pitch for him -- to strike out Emilio Bonifacio.

“This is pretty much where I expected to be if I had a healthy spring. I was able to do that,” Zimmermann said. “My body feels good going into the season, so I’m ready. I’m ready to get out of here and go play some meaningful games.”