Seattle trades for relief pitcher Rafael Montero

Just like Jerry Dipoto said at the beginning of the offseason, the Mariners are adding relievers in an effort to shore up a bullpen that was awful in 2020. Ranked 30th in FanGraphs WAR (fWAR), 28th in ERA, 30th in fielding independent pitching (FIP), and 30th in expected FIP (xFIP), the bullpen was something that had to be fixed in an effort to compete with a tough AL West. And while fixing the bullpen won’t make the Mariners immediate contenders in a tough division, it’s a volatile part of the game that makes it a little easier to contend sooner rather than later, even if you are rebuilding.

In this move, the Mariners acquired Rafael Montero from the Rangers for pitching prospect Jose Corniell and a player to be named later. Montero, once a highly-touted starting pitching prospect in the Mets organization, became a Ranger in 2019 and was converted to a bullpen role. Due to injury and poor performance, he only tallied more than 100 innings once in his four years with the Mets. The Rangers, however, found what might be considered a “diamond in the rough” with Montero in the bullpen. In 2019 and 2020 combined, Montero had a 3.09 ERA, 3.78 FIP, and 3.98 xFIP, along with a respectable 10.22 strikeouts per nine innings (K/9).

Looking at Montero’s numbers combined, however, hardly tells the whole story. That 3.09 ERA was brought to you by a fantastic 2019 ERA of 2.48, but an ERA of 4.08 in 2020. However, his 2020 ERA is still above average with an ERA- of 84, and with a FIP- of 81 and 80 in 2019 and 2020, respectively, and the regression of his 2019 ERA was not a surprise. What that shows us is that over the last two years, Montero was consistent, and consistency is key when it comes to the bullpen.

Another underlying factor that influenced his 2020 ERA to go over 4 is his left on base rate (LOB%). In 2019, Montero’s LOB% was 95.7%, second in the MLB for relievers with at least 20 innings pitched. I’m 2020, it shank down to 49.4%. The good thing to take away from this is that LOB% is typically used as a predictive stat, much like FIP. Believing that he will again regress towards the average and raise his LOB%, it’s not unlikely that his ERA will move back into the 3s and closer to his FIP in the 2021 season.

Overall, Montero has profiled well as a reliever over the past two seasons. He ranked in the 84th percentile for fastball velocity in 2020, according to Baseball Savant, and over the last two seasons his changeup has given up a batting average of .176 and a slugging percentage of .221.

The Mariners are sending prospect Jose Corniell and a PTBNL back to the Rangers in exchange for Montero. Corniell was a part of the Mariners 2019 international signing class. He was able to be a part of the Mariners’ Dominican Summer League team, but due to the loss of the 2020 MiLB season, he has not had the opportunity to pitch past that. Baseball America ranked him as the Mariners’ 22nd overall prospect in their 2020 midseason review. Not an incredibly high ranking, but a for a 17 year-old who never pitched in minor league ball, it could be seen as quite the vote of confidence.

Although I started this article with the sentiment that having a bullpen is necessary even during a rebuild, this trade is not my favorite for the Mariners. I think Montero would have been a great pickup for a team that is contending and not depending on what the farm system will bring in the future. Giving up a guy with major future upside like Corniell and another prospect to be named later for a 30 year-old reliever who has a very small sample size of success seems odd for a team that is clearly not yet ready to compete with the likes of the Astros, Athletics, or even the Angels; especially when there is quite literally a plethora of free-agent relievers on the market this offseason. I see this move as Jerry Dipoto trying to make good on his promise of adding “three or four” relievers this offseason without pulling out the checkbook. It was reported along with this trade by Jeff Passan and Shannon Drayer that the Mariners are interested in free-agent relievers Blake Treinen and Kenyan Middleton. However, if I had to guess, Treinen and Middleton proved to be too expensive, causing Dipoto to pull the trigger on the Montero trade.

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