Colorado Rockies' Rex Brothers Off To Unsustainable Start

By Gabe Isaacson
Richard Mackson-USA TODAY Sports


Pitchers generally develop certain skills with experience in the major leagues. For some pitchers, the manifests itself in the decrease of walks – like Adam Wainwright – or continually exceeding beyond their peripherals – like Matt Cain. For Colorado Rockies RP Rex Brothers, improvement has manifested itself in a variety of ways.

With a career low 0.31 ERA, Brothers’ success cannot be easily attributed to a change in skill-set. Brothers, in his third major-league season, actually has his lowest K/nine and highest BB/nine. His velocity is about the same, if not slightly worse, and he has clearly taken advantage of curious early season pitcher-friendly trends in Coors Field. Brothers has yet to allow a home run, and his advanced metrics do not support him sustaining this success.

Overachieving can take many forms, as can regression. Many pitchers who enjoy early season success also enjoy late season regression, but the true determinant is how steep the regression is. Brothers’ numbers indicate that he is in store for some of the most substantial regression of any pitcher in baseball. Brothers is enjoying a career best 0.31 ERA, but a career worst 3.88 xFIP. Though xFIP is not a useful indicator for pitchers that manipulate home runs at a substantially different rate than league average, it is fair for Brothers. xFIP utilizes a 10.5% HR/FB rate, and that is comparable to Brothers’ career average.

While Brothers has been one of the best relievers in baseball through the first two months, the Rockies will be thankful when closer Rafael Betancourt returns – as Brothers’ shift back towards his career norms could cost them runs and games in late-innings in the coming months.

Gabe Isaacson is a writer for Follow him on Twitter: @gabeisaacson.

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