#3 Justin Topa
After pitching a total of just 18 innings over three major league seasons with the Milwaukee Brewers, Topa was traded to Seattle in exchange for pitching prospect Joseph Hernandez. In his first full season, he was stellar out of the bullpen, recording a 2.61 ERA and 1.15 WHIP over 69 innings pitched.
Choosing soft contact over pure power, Topa's strikeout rate of just 21.9% was below league-average, but his ground-ball rate of 57.4% was in the top 6% of the league. This helped him post an opposing batter barrel rate of just 3.0%, better than 97% of MLB pitchers. That being said, he wasn't unwilling to paint the edges of the strike zone when necessary.
Because of his unusually low strikeout rates for a high-leverage reliever, the name Justin Topa didn't exactly jump out to most people as one of the best bullpen arms in baseball. As with most contact pitchers, it can be hard to say whether he "just got lucky" this year or if his success was due to intrinsically good pitching. However, his xERA of 2.97 shows that the numbers on paper were pretty much deserved. Additionally, while his whiff and chase rates are in the bottom quartile, his walk rate of just 6.5% means batters will have to go down looking or try their hand at avoiding one of his patented ground balls.
Because of this year's stellar infield defense, his pitching synergized extremely well with Seattle and may not find the same results with less defensively-focused teams. Mariners relievers combined for an ERA of 3.48, fourth-best in MLB, thanks in no small part to Topa. He won't be a free agent until 2027, so despite his stock being higher than ever before, it's important that the team holds onto him if they want to repeat their bullpen success from 2023.