What do you get when you take a player with very good tools and off-the-charts makeup? Often, you get a player like Jarred Kelenic, who will make his long-awaited Major League debut on Thursday.

The No. 1 prospect on the Mariners’ Top 30 prospects list and No. 4 on the Top 100, it would be easy to think Kelenic has been around forever given the amount of time and energy that has been used to discuss if and when he’d get called up to take his place in Seattle’s outfield for the first time. But Kelenic (pronounced KELL-nick) is just 21 years old and would be a college junior entering the Draft this year had he headed to college.

A product of the Wisconsin high school ranks, Kelenic was No. 10 on MLB Pipeline’s Draft Top 200 as the 2018 Draft approached. A Louisville recruit, Kelenic stood out for his advanced feel to hit, but it was unclear how much power he would generate from his 6-foot-1 frame or if he would be able to stay in center field long-term.

• Watch Kelenic’s debut: Free on MLB.tv; MLB Network (Thursday, 10:10 ET)

Still, he was the highest-ranked prep hitter in the class and was drafted as such, taken No. 6 overall by the Mets. It wasn’t a huge reach, but it was enough of one for him to sign for $1 million below slot. His time with his original organization was short-lived, as everyone knows by now, with the Mets sending Kelenic to the Mariners in what many feel will be known as the infamous Robinson Canó deal that offseason.

Kelenic has always been athletic and strong, but he showed up at Spring Training for his first full season with his new team having clearly hit the weight room hard. He’s never lacked confidence, with a swagger that always falls short of being too cocky for his own good, and it was clear he was out to prove just how good of a player he could be. He did that and then some, far outproducing any projections of what he might do by playing his way to Double-A in 2019 and finished with a 20-20 season and a .904 OPS.

That fall, Kelenic was slated to play in the Arizona Fall League and was upset about not being able to play immediately after getting his wisdom teeth removed. That should give some idea of what kind of attitude Kelenic will bring to the ballpark every day.

Since then, of course, we haven’t gotten to see much of the outfielder because of the pandemic, but it did seem like the Mariners’ player development Twitter account was posting video of a homer from him daily from the club’s alternate training site last summer. It was clear he was just about ready when he hit .300 with a pair of homers in big league camp this spring, then he hit .409/.458/.682 with two more homers and a pair of steals over his first five Triple-A games this season.

It appears the Draft projection of him being a plus hitter was spot on as he begins his big league career with a .293 average and .369 on-base percentage in a Minor League stint that has spanned 178 total games. He has a knack for barreling up the ball and can drive it to all fields while working counts and drawing walks, with a 10 percent walk rate in the Minors.

Kelenic has done that while largely limiting his strikeouts (21.4 percent), especially when considering he’s far outstripped his power projections. What was termed solid raw power was almost immediately turned into now power, with the 23 homers in his first full season. He generates the power naturally and doesn’t sell out for it, though he clearly knows how to turn on an inside pitch and pull it into the seats.

His speed has also trended up as a professional and he’s aggressive on the bases, with 37 steals in those 178 games. It’s also enabled him to go from a “he might not stick in center field” evaluation to a “he should be able to play center field long-term” report. And even if he did move to a corner, he has a plus arm that would look very good there.

The Mariners challenged Kelenic last summer, because of his stature as one of the best players on the field at any given time, to take on more of a leadership role and by all accounts, he embraced that challenge exceedingly well. That might take time at the big league level, but Kelenic will bring that sense of belonging with him right out of the gate.

His confidence should serve him well for whenever it is he faces adversity (something he’s seen little of to date). Even if he isn’t hitting, he can impact the game in a number of different ways, but he’s such a good hitter he should make adjustments quickly. Look for Kelenic to hit the ground running here, with the chance for him to be an All-Star performer who hits .300 and puts up 20-20 type numbers at the highest level, outshining what the industry thought he would become when he was drafted just three years ago.