Former Pirates reliever should be on their reunion radar after NPB breakout

The Pittsburgh Pirates' bullpen could use another reliever. Their depth chart already has a solid core in the pen, led by Dennis Santana, Justin Lawrence, Carmen Mlodzinski, and Isaac Mattson, with a strong supporting cast.

However, now that they traded David Bednar at the 2025 trade deadline and recentlynon-tendered Dauri Moreta, they could use some more depth. The Pirates should look to one of their former bullpen arms, who broke out big in Japan and may look to head back over to the United States in the form of right-hander Kyle Keller. He will soon become a free agent.

Keller spent the 2021 season with the Pirates. Purchased from the LA Angels, Keller appeared in 32 games with 33.1 innings pitched for the Bucs, but posted a poor 6.46 ERA, 6.95 FIP, and 1.56 WHIP. His 23.2% strikeout rate was the only thing he excelled at, but his 14.2% walk rate nearly completely negated it. Opposing batters annihilated Keller for a 90.2 MPH exit velocity, 14.1% barrel rate, and 2.43 HR/9 ratio.

After the 2021 season, Keller headed to Japan's Nippon Professional Baseball league, where he proceeded to become one of the league's best relievers. Over the 152.2 innings he has tallied in Japan, Keller owns a 2.42 ERA, 2.76 FIP, and 1.05 WHIP. His 10.1% walk rate still shows he has control issues, as it is the ninth-highest mark of any pitcher with at least 150 IP since the start of the 2022 season. On the flip side, his 28.8% K% is the fifth best, and his 18.7% K%-BB% is the 12th best.

If the Pirates want a low-risk, high-reward reliever to add to their pen, they need to look into old friend Kyle Keller.

The last time MLB batters saw Keller, he was primarily a two-pitch pitcher. He used a four-seam fastball that sat 94-95 MPH with above-average movement. His secondary offering was a low-80s curveball with average movement. Keller threw from a 51-degree arm angle while showing about average extension off the mound. The right-hander has also added a forkball to the mix.

If Keller opts to take his talents back to Major League Baseball, his contract would look similar to the one the San Diego Padres offered Woo-Suk Go during the 2023-2024 offseason. Although Go was coming from South Korea's KBO, Go had experience as a closer in Korea and was younger. Meanwhile Keller only saved seven games during his time in Japan, is older, but played in a better league. Plus, he is coming off a better season than Go did after 2023. Go ended up signing a two-year contract worth $4.5 million guaranteed.

A contract with an AAV around $2-$2.5 million is definitely up the Pirates' alley, and they would be adding a potentially good reliever in Keller on a low cost. Plus, they need to commit as much of their offseason funds as possible toward hitting, rather than pitching. Even if Keller becomes just a solid middle relief arm, rather than a dominant set-up man, the Pirates can use all the help they could get, and considering Keller would likely sign for a low cost, they should highly consider him as a free agent option if he decides to head stateside.