In their quest for a No. 5 starter, the Padres might have the answer in a former Rule 5 pick.

While that header sounds like something fans of the 2016-19 Padres might hear, the Padres of 2025 are a completely different animal. Fresh off a postseason berth, the team is looking to round out their rotation, and they have no shortage of options.

Of the six-plus candidates, Stephen Kolek might present the highest upside.

A year ago, that sentence would be blasphemy.

After all, Kolek was taken in the Rule 5 draft out of the Mariners’ system after the 2023 season. The right-hander had spent most of his career as a low-strikeout, high-ground ball starter before the Mariners converted him to a long reliever. His sinker/slider combination really played up in that role, allowing him to strike out 26% of opposing batters with a ground ball rate of 59%.

This ability to pitch multiple innings certainly stood out to the Padres, along with his mid-90s sinker and broad arsenal, as they selected him in the 2023 MLB Rule 5 Draft.

In the Major League phase of the 2023 Rule 5 Draft, we have selected RHP Stephen Kolek from the Seattle Mariners Triple-A roster. pic.twitter.com/vuiVVutnpl

— San Diego Padres (@Padres) December 6, 2023

Kolek’s debut campaign in the majors was a mixed bag, something of a statistically misleading season. The surface numbers will portray his performance as subpar, as a 5.21 ERA and 18.1% strikeout rate aren’t earth-shattering numbers. However, his advanced numbers portray a season of a pitcher who performed better than the ERA. Kolek walked a career-low 5.7% of opposing batters in 2024 with the Padres, and his 55.9% ground ball rate in 46.2 innings was the highest on the team (of pitchers with a minimum of 40 innings pitched). Kolek also saw career-worst numbers in home run-per-fly ball rate (12.9%) and BABIP (.359), but these were paired with a minuscule 3.8% barrel rate.

Much of the damage against Kolek came from ground balls hitting just the right spot; in other words, it was death by a million paper cuts.

When looking deep into the numbers from his performance, his Stuff+ metrics are a very telling detail. Kolek’s arsenal as a whole grades out as above-average per Stuff+, regardless of which variation of the stat you want to look at. FanGraphs’ Stuff+ metric gives his arsenal a 106 Stuff+, where 100 is league-average, and his sinker and slider grade out at 110 and 108, respectively.

Stephen Kolek made his Spring debut as he works towards transitioning into a starter this season

Understandably, his velocity was down but his stuff still looks decent. His trio of fastballs give him a solid foundation to build upon pic.twitter.com/Q28ykkYzGR

— Thomas Nestico (@TJStats) February 25, 2025

So if the stuff is as good as the numbers say, what gives?

Location, location, location.

While Kolek’s slider/sweeper was above average regarding the amount of horizontal break on them, batters made hard contact against the pitch because he would leave it in the middle of the zone. Of the four home runs that Kolek allowed in 2024, three came on sliders/sweepers left in the swing path of right-handed batters (Ezequiel Tovar, Christopher Morel, Travis d’Arnaud). This tandem of pitches ranked as average overall in Location+, indicating that Kolek was not able to locate it in a consistent manner. His other main offerings (fastball, sinker, changeup, cutter) all ranked above 110 in Location+, with his changeup registering a very strong 122 in Location+.

Ultimately, it is apparent that Kolek’s kitchen-sink arsenal would lend well to starting, as he has pitches to deal with batters from both sides, and his stuff is above average in terms of movement and pitch profiles. The right-hander made his Cactus League debut for the 2025 campaign on February 25, striking out two and throwing 80% of his pitches for strikes.

His pitches tunnel well off one another, allowing him to get chases on the breaking balls, as seen in 2024, and this facet of his game bodes well for his development as a Major League-caliber starter. Kolek also has a sufficient disparity in the way his arsenal moves to keep hitters guessing, as he can spin the baseball from 17.1 inches to the arm side all the way to 16.2 inches of glove-side movement. That’s just under a three-foot span of break from his arsenal, which allows him to locate on the corners when needed as well.

While it may be soon to call Kolek a full-blown breakout, as he needs to get through Spring Training proving he can be a starter, it is more likely than not that he makes a Major League start for the Padres in 2025. As said on our Padres EVT Podcast, one doesn’t take a long reliever in the Rule 5 and plan for him to just be a long reliever at the big league level. San Diego and A.J. Preller made a long-term play when taking Kolek in the Rule 5, without a doubt. It’s a very different situation than the Luis Perdomo/Allen Cordoba/Miguel Diaz picks.

Years ago, the Mariners acquired a relatively unknown prospect named Stephen Kolek for the lowly sum of $1. Now, years in the future, Kolek has the opportunity to become an impact member of the San Diego Padres’ pitching staff in pursuit of a championship.

Diego Garcia

A born and raised San Diegan, Diego Garcia is a lifetime Padres fan and self-proclaimed baseball nerd. Diego wrote about baseball on his own site between 2021-22 before joining the East Village Times team in 2024. He also posts baseball content on his YouTube channel “Stat Nerd Baseball”, creating content around trades, hypotheticals, player analyses, the San Diego Padres, and MLB as a whole.

A 2024 graduate of San Diego State, Diego aims to grow as a writer and content creator in the baseball community.