Who is Michael Petersen, the newest member of the Blue Jays?

The Toronto Blue Jays' first move of the offseason was claiming right-handed pitcher Michael Petersen off waivers from the Miami Marlins. While their bullpen struggles this past season require much more help than a depth arm like Petersen can offer, his value to this team certainly isn't nonexistent.

Petersen saw his first MLB action in 2024, splitting 16 appearances between stints with the Los Angeles Dodgers and Marlins. His 5.95 ERA across 19.2 innings may not be the most encouraging sign, but his recent track record dispels any worries this might cause.

Who is Michael Petersen, the newest member of the Blue Jays?

The time Petersen spent at the Triple-A level with the Dodgers' affiliate Oklahoma City Comets saw him succeed to a great extent, as he posted a marvelous 1.64 ERA and 2.29 FIP across 33 innings of work. He boasted excellent rate stats of 12 K/9 and 2.18 BB/9 and only surrendered three home runs in this sample size.

While there is an evident skill gap between the highest level of the minor leagues and the MLB, Petersen's proven at the second-highest level of play that he can find consistent success on the mound.

Petersen's inflated MLB ERA last year can be summed up through the situations in which he surrendered the most runs. Over half of his 14 earned runs were surrendered in blowout games in which his team was losing by at least four runs. But did he perform well when he pitched in tight situations?

Actually, yes, he was very successful in high-stress situations last year. Average leverage index (aLI) is a statistic that denotes the intensity of any given outing for a pitcher, where 1.00 is average and any higher number represents more intensity and vice versa for lower numbers. In all of Petersen's outings in the MLB that had aLI values of 1.00 or higher, he had an ERA of just 1.42.

The arsenal he brings to the mound is less impressive, however, as he only really works with a fastball/cutter combo with the (very) rare changeup or slider. His fastball averaged 97.1 mph in 2024, so he's working with good stuff, even if he doesn't throw much else.

The only real problem with Peterson's game on the mound is his control issues. He walked 11 batters in just 19.2 innings, which was in stark contrast to his stellar walk rate in Triple-A this year. This could be chalked up to jitters at the MLB level, but the high levels of walks could definitely be concerning.

Peterson is by no means the solution to Toronto's bullpen problems, but hopefully he's just the start of acquisitions. The Jays are rumored to be looking at some of the best relief pitching talent in the offseason, including Milwaukee Brewers closer Devin Williams, so this might be a sign of improvements coming in free agency.

Peterson might find his way onto the Jays' MLB roster this season but will certainly be in contention for a depth role. If Toronto doesn't make some big moves to bolster their struggling pen, he could play a prominent role in relief. He's an interesting pitcher, to be sure, and hopefully he can be a difference-maker for Toronto.

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