Are William Contreras's Backpick Attempts Worth It?

The Brewers’ Tuesday evening affair with the Rockies was another chaotic battle at Coors Field. Lead changes in consecutive half-innings culminated in a Milwaukee win.

Before Milwaukee's ninth-inning comeback, Colorado took the lead in the bottom of the eighth against Bryan Hudson, in a sequence that featured a William Contreras throwing error on a backpick attempt at first base. Ryan McMahon advanced to second on the play, enabling him to score on a Brenton Doyle double a few pitches later.

Contreras worked to make the backpick a bigger part of his defensive toolbelt in spring training and threw to bases frequently throughout Cactus League play. He has carried it into the regular season, attempting a league-leading 29 backpicks. The next closest is Jonah Heim, who has attempted 17.

Contreras and the Brewers seem to view the backpick as a useful part of his repertoire behind the plate. Tuesday evening’s play demonstrated its potential downside, though. Is it truly valuable, or is it a risky move with minimal payoff?

The purpose of the backpick is to establish greater control over the running game. It rarely produces an out. Just 5% of all backpick attempts (17 of 338 throws) have resulted in a pickoff this year, while 3.6% (12 throws) have resulted in throwing errors that moved the runner up by at least one base.

Two of Contreras’ 29 backpicks have resulted in a pickoff, and two have resulted in an error. That’s an equal rate of 6.9% for both outcomes.

Most of his backpicks have resulted in a neutral result, and they’ve been equally as likely to produce a negative outcome as a positive one. Contreras has been nearly twice as prone to allowing extra bases on a backpick as the average catcher. However, the value of an out is usually greater than that of an extra base, so according to some rudimentary run expectancy math, the Brewers have come out slightly ahead on his pickoff attempts.

Determining the value of the backpick is far more nuanced than that simple comparison, though. The threat of a pickoff by a catcher is supposed to deter the runner, by convincing them to reduce their lead off the base and making them less likely to attempt a steal. That effect is not reflected in the outcome of the backpick itself.

Contreras only backpicked twice last season, and was a below-average catcher at controlling the running game. Opponents attempted a steal on 6.7% of opportunities, and his 17.2% caught stealing rate was a couple of ticks below the league average of 19.8%.

Stolen base success rates have decreased across baseball this year, but Contreras’s gains in that department have outpaced the rest of the league. Opponents are running against him on 5.4% of opportunities, and he’s upped his caught-stealing rate to a league-average 22%. Based on those figures, Contreras has gone from below-average to solid at controlling the running game.

Quote

For more on Contreras's dedication to this aspect of defense, check out Matthew Trueblood's piece about his throws behind runners and on steal attempts, from late April.

The Hunter: William Contreras's Fight to Control the Running Game

This is an admittedly imperfect analysis. Some of it could be rendered moot, given that holding runners is mainly the responsibility of the pitcher, not the catcher. Pat Murphy said last month that he believes pitchers bear “probably more than 80%” of the responsibility for the running game. Varying looks and timing on the mound is more impactful than the catcher's actions. On the other hand, under pitch-timer rules, pitchers are almost confined to that kind of deterrence.

Globally, the league takes off and attempts a steal in about 6.6% of their opportunities. After one disengagement within a plate appearance, though, that rate climbs to 17.0%, and after a second disengagement, it climbs to 24.4%. Since the rules provide for a balk and automatic advancement if there's a third disengagement without an out being recorded, every throw over from the mound emboldens a runner. A catcher can fill the gap, because throwing behind runners doesn't count as a disengagement--but, of course, it also comes after the fact of the pitch, so it only deters those runners who are practicing lengthening their lead but not yet ready to go for it. 

Contreras backpicking may or may not be helpful. Regardless of how one processes the improvements to his stolen base metrics, the evidence indicates that the backpick is unlikely to hurt the Brewers in any meaningful way throughout a season, so why not try it? That may be the real takeaway here, and it could be part of the thought process in Milwaukee permitting its catcher to throw to bases so frequently.