This story was excerpted from Mandy Bell’s Guardians Beat newsletter. To read the full newsletter, click here. And subscribe to get it regularly in your inbox.

It’s been a long road for Joey Cantillo, but the 24-year-old lefty from Hawaii finally made his Major League debut in Sunday afternoon's series finale against the Phillies at Citizens Bank Park.

The Guardians’ No. 10 prospect, as ranked by MLB Pipeline, joined Cleveland’s organization in 2020 as part of the trade that sent Mike Clevinger to the Padres. Since then, Cantillo has blossomed as he’s worked with the club’s famous pitching development team, and he's now had the chance to put his skills on display against the best team in the Majors.

No pressure, right?

Let’s look at three things that are important to know about him.

Why not sooner?
In a perfect world, Cantillo would’ve already made his Major League debut, but that’s not how the chips fell for him.

In Cantillo's first two seasons with the Guardians, oblique and left shoulder issues limited his playing time. He was determined to focus on taking care of his body in the winter leading up to the 2023 season, and it worked, as he stayed healthy all year long, making 26 appearances. The first six of those came with Double-A Akron, where he dominated his opponents, owning a 1.85 ERA in 24 1/3 frames. He quickly was promoted to Triple-A Columbus, but there, he didn’t have the same success there. Cantillo fell behind in counts pretty consistently and wasn’t efficient enough to get deep into his outings. As much as he wanted ’23 to be his debut season, he needed to wait at least another year.

The Guardians entered 2024 with unusually thin starting pitching depth. It seemed clear from the start that Cantillo’s debut was inevitable, and when Shane Bieber went down due to a right ulnar collateral ligament injury in the first week of the season, it became even clearer that Cantillo would be needed. The problem was … Cantillo was hurt again.

This time, Cantillo suffered a left hamstring strain and didn’t get on the rubber for Columbus until the first week of June. His timeline had to be pushed back yet again, but Cantillo finally got the chance to make his long-awaited debut, striking out three while allowing three runs on two Kyle Schwarber homers over 3 1/3 innings.

The arsenal
Cantillo throws a fastball, a curveball, a slider and a changeup. Although his changeup is known to be his best weapon, we have to take a second to focus on the growth of his heater.

Cantillo's fastball velocity sat around 90 mph in his first five years in pro ball. But after working with Cleveland’s pitching development team, that fastball now sits at 92-95 mph and can reach 98 with carry when he commands it up in the zone.

That velocity helps make Cantillo's changeup even better, creating more separation between the two pitches, as his Vulcan changeup ranges from 79-82 mph before diving at the plate.

What he needs to prove
The Guardians desperately need starting pitching help. There’s no doubt that the front office will continue to make dozens of phone calls leading up to Tuesday’s 6 p.m. ET Trade Deadline in order to try to add more options to the roster. But if they can’t do that, internal hurlers – like Cantillo – become even more invaluable.

If Cantillo can find success in the big leagues, the Guardians will be able to take at least a baby-sized sigh of relief. But he’s far from a guarantee. Cleveland will need to see that Cantillo can keep his walk rate down. In eight starts in Triple-A this year, he’s only had one outing with zero walks, and he issued four free passes in three of them. In all of ’23, he averaged 5.2 walks per nine innings, and his total this year is 19 walks in 29 frames.

And that changeup we talked about? It has the possibility of being electric, but it also may not play as well in the big leagues as it has in the Minors. So far, Cantillo has been able to get more chase on the offering than called strikes, which more disciplined hitters may be able to lay off of.

But if Cantillo can pound the strike zone, avoid walks and be efficient enough to eat up innings consistently, he could prove to be a mainstay in this rotation. His journey to prove that begins now.