The Miami Marlins have gotten a lot of unexpected contributions from various players on their team, and one of them has been from second-year second baseman Derek Dietrich. He has utilized a new, patient approach to great success at the plate, as he is hitting .246/.350/.432 (.351 ISO) with five homers. The Marlins have to be happ with his offensive contributions so far this season.
It has been on the defensive side where Dietrich has struggled. After committing just two errors in 2013, he has already committed seven errors in 2014, with four of them in the fielding department and three on errant throws. The metrics have not been kind on Dietrich either, as he has been evaluated as bad as four runs below average so far this year (though Baseball Prospectus's FRAA has him as above average). The errors cost Dietrich some playing time earlier this season, as manager Mike Redmond benched Dietrich to help "regain confidence" earlier this season.
The Marlins' best second base option right now is Dietrich, especially with free agent addition Rafael Furcal moved to the 60-day disabled list. But the question of his defensive play is important. Based on what we have seen so far, how does Dietrich compare in the metrics? We take a look at available information on FanGraphs to determine.
For Dietrich, the defensive metrics have not helped his case. Both UZR and DRS have him rated as a bad defender, between seven and 10 runs worse than average in just 772 innings at the position. Prorated out to a reasonably full season (1200 innings) and you get a rate of 13 runs worse than average. Even with regression, it is likely that, from what we have seen, Dietrich is a below-average defender at the position.
Then again, there are enough discrepancies in defensive metrics and not enough of a sample size to determine how much of a liability Dietrich likely is. For that, we should turn to scouting-style resources and see what that information can glean about his current performance.
Fans Scouting Report
Dietrich played 57 games at second base last season and was evaluated by three Marlins fans in the Fans Scouting Report. With such few votes, I am not certain we got an honest evaluation of Dietrich, but it is worth looking at how he fared versus the sample of other second basemen. Among 44 players with at least 500 innings at the position, Dietrich ranked 28th and was given an average defensive rating. Given that second base is considered a "neutral" defensive position and not necessarily a premium spot, that would make him close to an average player at second.
What other players ranked similarly? Similarly rated names included Donovan Solano (considered in Miami circles as a good defender), Josh Rutledge, and Jedd Gyorko. None of those defenders really inspire any confidence, and many would probably be considered average to a bit below average. A little higher on the list are similar names like Jason Kipnis and Neil Walker, and a bit below Dietrich are guys like Jose Altuve and Daniel Descalso. Again, those names are not far-fetched comparisons, and they are all below average defenders.
I took the five names in front and behind Dietrich in the Fans Scouting Report and examined their defensive statistics to see a profile of similar players. The average of those players' season UZR rates ended up being +0.8 runs per year, or essentially league average play.
Inside Edge Fielding
The latest tool available on FanGraphs for fielding evaluation is the Inside Edge fielding numbers. Inside Edge grades plays on difficulty and determines how well players do on those plays. In the last season-plus, Dietrich has not done well in this department. On plays rated "routine," defined as those that should be made 90 to 100 percent of the time, Dietrich has converted on 96.6 percent of them. Since 2011, only one second baseman with at least 1000 innings on the job has converted at or below that mark on those types of plays, and that is Jemile Weeks, who is well known as a poor second baseman.
The majority of what is considered the league's worst second basemen have converted on around 97.5 percent of "routine" plays. That includes guys like Dan Uggla (97.5), Ian Kinsler (97.5), Daniel Murphy (97.6), and Kipnis (97.8). Contrast that with some of the most well-regarded defensive second basemen, who convert on 98.5 percent or more of those plays. Guys like Dustin Pedroia (99.2) and Ben Zobrist (98.8) are only getting to one percent more of those balls. If players get about 390 routine plays per season, missing out on one percent of those balls means losing out on
39 balls in play just about four plays a season, or almost three runs a season. That in and of itself is not a major difference, which means the addition of plays out of the routine zones need to be considered as well. (Editor's note: I'm not great at math sometimes. Thanks to Plaz for pointing out my mistake. Ugh. -MJ)
Right now, Dietrich has faltered in getting to balls that he should getting to. Part of that is on his streak of errors, but he is clearly making other mistakes that are costing the Marlins runs. Based on all of the numbers shown here, he has so far performed at a decently below-average clip, and he needs to right the ship soon or risk becoming a defender like Uggla who is known for poor play.