News broke on Tuesday afternoon that Didi Gregorius would miss approximately six weeks with a shoulder strain. With that came a flurry of speculation as to who would take over at shortstop when the Yankees break from camp in less than two weeks. Would it be utility infielder Ronald Torreyes? Or maybe former Mets shortstop Ruben Tejada? Perhaps the team will continue the youth movement and opt for a prospect like Tyler Wade. A number of options popped up around the internet.
A less popular suggestion, however, involves sliding second baseman Starlin Castro over to his natural position. Reports that Castro would play a few games at shortstop to shake off the rust were met with audible groans. Just look at some of the comments in that link. Yankees fans aren’t the the only ones skeptical of this solution, however. Even members of the Yankees beat voiced their concern.
Moving Castro to SS doesn't make sense. #Yankees didn't give him an inning there this spring for a reason: He can't be counted on there.— Brendan Kuty (@BrendanKutyNJ) March 21, 2017
Preferring an alternative to Castro at shortstop is a reasonable opinion. However, underselling his game at the position doesn’t paint an accurate picture. Kuty’s tweet is especially misleading when one considers the context. The Yankees didn’t play Castro at shortstop earlier in the spring because they didn’t anticipate a Gregorius injury. With a small army of shortstop prospects, it made more sense to get a look at them while Castro accrued innings at second base. The situation changed, however, when Gregorius hit the shelf. Smart teams adjust for variable circumstances.
Also, it’s worth noting that Castro isn’t a particularly bad shortstop. He’s not Omar Vizquel, but he’s not a potted plant either. He wasn’t moved off of the position in Chicago because he played poorly; he moved to accommodate Addison Russell. Likewise, he hasn’t played the position with the Yankees in deference to Gregorius. To gain some perspective, it makes sense to look at a few of the defensive metrics. I’m holding out 2016, when Castro only played 20 innings at shortstop.
Starlin Casto Defense at Shortstop, 2010 - 2015
It’s useful to chime in here with a quick primer on the metrics. One of the more popular defensive measurements in the sabermetric community is Ultimate Zone Rating (UZR). According to Fangraphs, UZR is a linear weight model which “estimates each fielder’s defensive contribution in theoretical runs above or below an average fielder at his position in that player’s league and year.” The average baseline for comparisons to a fielder in the same league and the same year is set at zero. According to UZR then, Castro’s only above average seasons come in 2012 and 2015.
Defensive Runs Saved (DRS), the other measurement used, operates similar to WAR. Per Fangraphs, this metric “tells you how many runs better or worse that player has been relative to the average player at his position. A +5 DRS at third means the player is five runs better than the average third baseman.” Once again, Castro grades out as a below-average shortstop, 2012 notwithstanding.
The eye test, however, says otherwise. There are several distinct moments that stand out from Castro’s highlight reel that make him look like a serviceable shortstop. Take this diving stop and throw for example.
There’s also this impressive basket catch.
How does one resolve such a discrepancy between the data and the on-field appearance? Fangraphs offers some assistance with their Inside Edge fielding metrics, which categorizes plays made by order of difficulty. This data goes back to 2012, which is important to remember when comparing to earlier charts.
The image shows us that Castro makes the routine plays. He does what he absolutely needs to do. He’ll even throw in a dazzling play every now and then. This visual also shows off his range, particularly to the third base side. This isn’t great, but it offers a more optimistic take than UZR or DRS.
For comparison’s sake, here’s Derek Jeter’s Inside Edge spray chart:
There’s far less range, almost none to his left, and no chance of making a difficult play. Castro’s defense at shortstop might be suspect, but it’s hardly Jeterian.
Moving Castro back to his natural position seems like the most logical outcome as the season approaches. He isn’t the best defender, but he can handle the position. It also would allow Torreyes or Rob Refsnyder to take over at second base, and neither of those substitutions require a 40-man roster move. Losing Gregorius for an extended period of time is certainly a blow to the team on both sides of the ball. It’s not a catastrophe, however, to temporarily replace him with Castro. It’s likely the best option available.
Data courtesy of Fangraphs.