Caleb Killian Is Proving To Be More Than a Feel-Good Homecoming

Going into this past winter, an improved bullpen was a clear need for the San Francisco Giants. They had dealt several of their best relievers at the previous deadline and lost their most reliable arm to Tommy John surgery.

There was some significant work to be done by Buster Posey and company, but it never really happened. The two most significant additions — Jason Foley and Sam Hentges — had both missed the majority of the last year with injury and were unavailable for Opening Day.

The front office opted for a handful of guys coming off of injury and several minor league free agents. One of those names was a familiar face who has become a key piece of what has turned into a fairly reliable group.

Stats were taken prior to play on April 29.

The Journey

Back in the eighth round of the 2019 draft, the Giants decided to select Caleb Kilian, a right-handed pitcher out of Texas Tech. He would debut later that year and not allow a run through his first 16 professional innings.

Due to there not being a minor league season in 2020, the organization would have to wait until 2021 to see the then 24-year-old throw again. It would end up being worth the wait, as in Double-A Richmond that year, Kilian would toss 63 innings to the tune of a 2.43 ERA.

He was starting to make some waves in the prospect world and had finally found his way into the Giants top 30 prospects across the industry. However, things would take a quick turn for Kilian in the middle of that year.

It just so happened that the Giants’ big-league club was in the midst of a historic — and frankly surprising — season in which they would finish with 107 wins and a NL West division title.

To further their World Series chances, they decided to trade for one of the biggest names in baseball at the time — Kris Bryant. Kilian, the rising right-hander, was part of the package to go back to Chicago in the deal.

Years down the road, the deal looked like an absolute steal for the Giants. While Bryant would eventually sign with the Rockies in free agency after that season, he provided solid production for the club.

His numbers in the 51 games after the trade deadline were fine, but it was what he did in the postseason that made the deal well worth it. In five games against the division rival Dodgers in the NLDS, Bryant would hit .471 with a 214 wRC+ and a late home run to help secure a series-opening win.

The Giants eventually lost in five to the Dodgers, but Kilian and Alexander Canario (the other prospect sent to Chicago) did virtually nothing for the Cubs during their tenure in Chicago. Kilian threw just 27.1 innings for the Cubs across three years and struggled, with a 9.22 ERA while striking out just 6.91 hitters per nine innings.

Fast-Forward

Now, we can come back to this offseason when Buster Posey clearly needed to find some solutions in the bullpen. Kilian would be one of the first names he turned to.

On December 14, we got word that the Giants had signed him to a minor league contract. Of course, fans loved the idea of him returning to the organization simply for the story, but nobody believed he’d be a real option.

He had been a starter for the entirety of his professional career and didn’t have the stuff of an effective big-league reliever. However, just a few days into spring training, that stigma would change.

The stuff was on a completely different stratosphere from where it had been in his previous time in the big leagues, and while it was just Spring Training, he was dominating.

In 9.1 Cactus League innings, he struck out over 30% of hitters with a 0.96 ERA. The performance led to him making San Francisco’s Opening Day roster and quickly proving to be a key arm in the bullpen.

In 12 innings up to this point of 2026, Kilian has a minuscule 0.75 ERA with a 10.5 K/9, 54.2% ground-ball rate, and team-leading .103 average against. This is all thanks to an absurd uptick in velocity and stuff overall.

	FA	SI	SL	KC
2024	93.6 mph	92.4 mph	80.1 mph	76.3 mph
2026	97.0 mph	95.8 mph	88.2 mph	80.8 mph

The other major adjustment has been significantly more trust in his knuckle curve. In 2024, Kilian threw the pitch just 4.8% of the time. In 2026 so far, he’s thrown it nearly 30% of the time.

It’s led to a major jump in whiff and overall effectiveness in his time as a full-time reliever at the big-league level. All of a sudden, the Giants look to have another hard-throwing right-hander who they can trust in the late innings of big games.

Of course it’s early, but the initial returns are extremely encouraging.

Final Thoughts

For a guy that had been dealt from the organization more than four years ago, Kilian is taking full advantage of his second stint with the Giants. The development of him as a high-leverage arm has turned what looked like a pretty good trade into a flat-out fleece.

Kilian not only failed to make real contributions for the Cubs’ organization, but he has now returned to his initial ball club as a legit backend arm in the bullpen. While we could easily chalk this up as a feel-good homecoming for the now 28-year-old, it is proving to be much more than that.

If his team can turn things around, we may just see the rejuvenated arm of Caleb Kilian throw important innings for the San Francisco Giants down the line in 2026.