Casey Mize struck out nine batters in four innings Thursday night and afterward said he pitched like he had something to prove. His manager watched from the dugout and on Friday morning gave him the news he’d been waiting to hear.

“He’s going to be in our rotation,” A.J. Hinch said.

That means Detroit’s Opening Day rotation is set, with MLB Pipeline’s No. 11 (Mize) and No. 24 (Tarik Skubal) prospects on it. Opening Day starter Matthew Boyd and veterans Julio Teheran and José Ureña round out the rotation. Spencer Turnbull will open the season on the injured list; he remains in COVID-19 protocol.

Former All-Star and 2016 AL Rookie of the Year Award winner Michael Fulmer, who finished an up-and-down Spring Training with two strong outings in long relief, will open the season in the bullpen, according to Hinch.

Though the timing of the announcement suggested Mize’s outing Thursday was a deciding factor in starting him over Fulmer, Hinch said it was not the determining factor.

“This is a longer view for these guys, so it wasn’t all based on [Thursday's performance],” Hinch said. “The longer view of it is twofold. Number one is we think Mize has continued to pitch better than his numbers indicated in the spring. And [Thursday] night, I do think he proved to himself more than he needed to prove to us that working in the strike zone is much more advantageous to him than kind of dancing around the strike zone. So it factored in a little bit. I wouldn’t say a lot.”

Mize walked three batters in each of his first three outings, racking up nine free passes over 6 1/3 innings. He had no walks and just two three-ball counts on Thursday, and he threw 55 of 72 pitches for strikes.

Fulmer, too, was his effective past couple of outings after struggling early in camp. The fact that those outings came in relief was the second factor.

“Michael Fulmer, I think we found something with him pitching with conviction out of the pen,” Hinch continued. “I don’t think his days starting are over; he’s likely to start games for us at some point. But I’m not necessarily going to wait for three- and four-inning stints to pitch him out of the pen.”

Much like Hinch said last week he believes Daniel Norris can be a weapon out of the bullpen, Hinch is going to look at situations and matchups to use Fulmer.

“I don’t want the mindset that they are long guys; I don’t like that term,” Hinch said. “I think they can provide length. They certainly can provide versatility for us in the 'pen. But if they are the best option to get us either out of a jam or pitch any particular inning that helps lead us to a win, then I need to be open to using them at that point. That’s their mindset. That’s going to be my mindset.”

A season-opening stint in Toledo, Ohio, to keep Fulmer stretched out, Hinch said, was not a serious discussion.

“Michael Fulmer is a big league pitcher and he deserves to be here,” Hinch said. “He made our team. We didn’t talk about any other scenario. ... There was no reason to send him down for any reason at all.”

Holland makes bullpen
Left-hander Derek Holland has also made the Tigers roster, as a reliever. The 34-year-old joined camp as a non-roster invitee and delivered eight scoreless innings on five hits with a walk and 13 strikeouts this spring, forcing his way into a Detroit bullpen that appeared to be largely set.

“He outpitched everybody that he was in competition with,” Hinch said. “He had to prove his way onto our 40-man [roster] and then onto our 26-man, and he found a little niche.”

That niche is something the Tigers envisioned when signing Holland, based on his limited work out of the bullpen in Pittsburgh late last season, from an uptick in velocity to a better strikeout rate.

“That trend continued when he got here, and he’s done everything imaginable to make our team," Hinch said. "I think he can be a short reliever. I think he can be a long reliever, even though I hate that term. He can provide a lot of versatile innings for us.”

Cameron optioned
The Tigers’ lone technical roster move Friday was optioning outfielder Daz Cameron to Triple-A Toledo. Detroit’s No. 11 prospect had been expected to open the season there, but he stayed in big league camp until the end as he worked back from right elbow issues that dated back to winter ball.

Cameron will report to the alternate training site to begin the season and work in center field as well as the corners. Before that, he’ll rejoin the Tigers for Sunday’s Grapefruit League game against the Blue Jays and play center in the late innings.

Quick hits
• Turnbull remains away from the Tigers complex while waiting to be cleared from COVID-19 protocol, and it remains to be seen whether he’ll be able to rejoin the team before it heads to Detroit. “It’s going to be a toss-up whether or not we see him physically in the building before we break camp,” Hinch said.

• The Tigers had a brief injury scare during Friday’s 5-2 win over the Pirates at LECOM Park when Harold Castro slid awkwardly into second base following an RBI single that turned into a rundown double play. Castro, who remains in the hunt for a utility spot on the Tigers roster, stayed in the game after being examined by athletic trainer Matt Rankin. He was already scheduled not to play Saturday.

• Matthew Boyd had the deepest Spring Training start of his career Friday, striking out six Pirates over 5 1/3 innings of two-run ball in just 75 pitches, 52 of them strikes. He needed just 26 pitches and 22 strikes to pitch the first three innings in his final tuneup before his Opening Day start Thursday against Cleveland at Comerica Park.

“I went out there wanting to be on the attack and pitch with tempo,” said Boyd, who finished his spring with a 2.45 ERA over five starts.