LAKELAND, Fla. -- Of all the negotiations the Tigers had during the offseason, Reese Olson could have had the toughest if he’d wanted. It wasn’t about his contract, but his jersey.

When Jack Flaherty signed his one-year, $14 million deal with the Tigers in December, he asked about getting No. 45, the number Olson wore during his breakout season in Detroit last year. It was partly a tribute to Hall of Famer Bob Gibson, with whom Flaherty had talked often during his years as a Cardinal, and the late Tyler Skaggs.

Olson could have held out for a jackpot. Instead, he gave it up in exchange for jerseys with his new No. 40 for his mom and his girlfriend.

Olson couldn’t care less about either number. He cares about being on the mound at Comerica Park, whatever number he’s wearing. He was on the mound for the Tigers’ Spring Training opener against the Yankees on Saturday at Joker Marchant Stadium, a 22-10 loss.

The Tigers essentially have six starters vying for five spots. Olson is the only one with less than a full year of experience, but he also has some of the most electric stuff of the bunch when he’s right.

The basic numbers -- 5-7 record, 3.99 ERA, 4.01 FIP and 8.9 strikeouts per nine innings over 21 games -- don’t accurately portray the impact Olson made following his June promotion from Triple-A Toledo. He struck out nine over 5 1/3 innings of one-run ball against the Twins for his first MLB win June 24, then fanned eight over six scoreless innings vs. Minnesota for his second win on Aug. 10. He tossed seven scoreless innings on Sept. 2 to beat the White Sox. He outpitched Dodgers rookie Bobby Miller with six innings of one-run ball in a win at Dodger Stadium on Sept. 20.

Then there were the metrics. His slider averaged 2,989 rpm of spin, second only to Reds reliever Lucas Sims among MLB pitchers who threw at least 500 sliders last year, according to Statcast. He had five of the top 26 individual sliders for spin rate, including a 3,259 rpm spinner just off the plate for a strikeout of Royals rookie Samad Taylor on June 19.

Opponents hit just .217 (26-for-120) off the slider with a 41.6 percent whiff rate, according to Statcast. However, six of those 26 hits went for home runs, comprising nearly half of the 14 he allowed for the season, and eight went for doubles. His fastball averaged 94.8 mph and allowed just a .179 batting average (19-for-106), but six of those hits were homers as well.

But beyond pitch selection was another trend: Six of Olson’s 14 homers allowed came when he was behind in the count, despite allowing just a .191 average (21-for-110) in those situations.

Olson’s 63.1 percent strike rate last year was slightly below the 64 percent average for MLB, according to Baseball Reference. His 47.3 percent strike-zone rate was similarly below the 48.6 percent MLB rate, per Statcast. Yet he also drew a higher percentage of called and swinging strikes than the MLB average, partly because hitters didn’t foul off his pitches as much.

“He demonstrated that he was a good strike thrower,” manager A.J. Hinch said. “He got a ton of miss on his secondary pitches. He got into a lot of two-strike counts, and that kept him very effective. So I’m more interested in that: As he tries to refine his stuff and tweak his usage a little bit, does he stay stubborn in the strike zone? That’s the No. 1 goal for him, and I expect him to do it. He’s very coachable, he’s very adaptable, but this spring is a lot different than last spring. Last spring, he was just trying to get healthy. This spring, he’s trying to stay at the highest level.”

Saturday’s performance left room for improvement. Though Olson spun some wicked sliders, topping out at 3,095 rpm, he yanked pitches and struggled with command. He walked three batters and hit another over his 1 2/3 innings. He threw just 16 of 39 pitches for strikes, including five called strikes.

“My metrics are going to be there,” Olson said of his pitches. “It’s just a matter of getting in the zone. I’m not worried about the shape or anything on my pitches. Just gotta get back in the zone.”

There was still a silver lining to Olson’s afternoon: Flaherty delivered the jerseys Saturday, and there’s a surprise gift on the way.

“He said he has something else coming,” Olson said. “We’ll see what he’s got.”