The mystery of Red Sox outfielder Hunter Renfroe’s defensive ability
Hunter Renfroe quickly developed a reputation as a strong-armed defensive presence early in his first season with the Boston Red Sox. As the season winds down to the stretch run, a review of his defensive metrics would seem to disagree with that initial assessment.
Renfroe has never been known as a speedster but he moves well for a player his size and has admirably covered Fenway Park’s spacious right field and navigated its quirky corners.
The narrative that Renfroe is one of the league’s top defensive right fielders is built on his major league leading 16 outfield assists. His right arm is a cannon that has routinely led to fans gleefully shouting at opponents that “You don’t run on Hunter Renfroe!”
FanGraphs tracks outfield arm runs, which credit’s an outfielder (plus or minus) depending on what the runners do on a hit or a fly ball out. Renfroe is sixth in the AL with 2.2 ARM, which shows his arm is an asset, right? That depends on which source you use.
Baseball-Reference uses a statistic called Total Zone Outfield Arm Runs Above Average (Rof), which measures the number of runs the player is worth based on base runner kills and advances. You would expect an outfielder who leads in assists would dominate this category as well but that’s not the case for Renfroe, who rates with a disappointing -1 Rof this season.
Renfroe has made many highlight-worthy throws to gun down opposing base runners but he’s also piled up his fair share of mistakes. He committed his 12th error of the season on Wednesday in Seattle on a poor throw that allowed runners to advance and a run to cross the plate. That error total leads all major league outfielders and doubles any other American League outfielder.
If leading the majors in errors at his position wasn’t bad enough, Renfroe is on the verge of historical ineptitude for this era. Since 1970, only 33 major league outfielders have committed more than 12 errors in a season. It’s only happened once in the 21st century when Justin Upton committed 13 errors in 2011.
While errors are clearly a negative for any player, most of us have moved beyond the archaic reliance on fielding percentage as the best measure of defensive value. We now use many different metrics to evaluate defense but one of the more widely used stats to measure a player’s overall defensive performance is Defensive Runs Saved. By this metric, Renfore rates slightly below-average with -1 DRS.
Statcast is slightly harsher, rating Renfroe as -2 Outs Above Average and -2 runs prevented. He isn’t among the bottom-10 right fielders in the majors but he’s clearly below average by these metrics.
Ultimate Zone Rating doesn’t view Renfroe favorably either with a -1.2 UZR. There’s a lot of ground to cover in right field at Fenway but he’s still below average, ranking just inside the top-30 major league outfielders.
More often than not, Renfroe passes the eye test. His strong throwing arm is a threat to keep runners in check and he’ll make the occasional jaw-dropping play. Unfortunately, he’ll also unleash throws he probably shouldn’t attempt, leading to several of those throwing errors.
When factoring in Fenway’s notoriously challenging right field, Renfroe has been solid at the position during his first season in Boston. He hasn’t played as poorly as some of these metrics suggest but he’s not a Gold Glove candidate either. Renfore is an average or slightly below-average right fielder with the upside to improve as he gets more comfortable in his home ballpark and cleans up his mistakes.