When I took a look at advanced fielding stats last week, I noticed that Nyjer Morgan was well below league average at CF--for the second update in a row. "Coincidence," I thought, "statistical fluke." UZR takes time to settle down, and a few early misplays might skew things. Then I saw last night's update. Given a Nat fan's natural tendency to panic, I decided to take a look at other advanced fielding metrics.
Three easily-available advanced defensive metrics are UZR, Defensive Runs Saved, and Total Zone Runs (find UZR at fangraphs, DRS and TZR at baseball-reference). Each basically works by assigning each position a certain zone(s) on the field and then adding up how many plays fielders make on balls hit to their zone(s). The stats compare each fielder to their position's league average to find how many runs they save/cost their team. (The details are complicated: each approach has its own zones and data sources, and there are different ways to account for things like holding runners, double plays, fielding bunts, ballpark differences, etc--the broad principles are similar.) League average is always 0: a positive number is good, and a negative number is bad. I've converted runs to date in 2010 to a yearly rate based on 135 games (note, UZR rate is usually per 150 games), and it takes about 10 runs to gain/lose a win. Here's a table comparing the three stats for Nyjer in CF in 2010, and career.
| 2010 Runs | 2010 Runs/yr | Career runs/yr | |
| UZR | -5.7 | -23.6 | +15.8 |
| DRS | -5 | -24 | +16 |
| TZR | -6 | -26 | +19 |
Right now, T. Plush is on pace to cost the Nationals 4 wins compared to his career numbers in CF. After the jump, a look at some traditional defensive measures, too. What's up with Plush?
In all cases, I'm just looking at Morgan's stats in CF (in 2010, career, and in other years), and I'm only comparing him to other NL CF or to NL-average in CF.
Nyjer has made 3 errors so far this season, worst in the NL. His 74 total chances (69 putouts, 2 assists) give him a fielding percentage of .960--also worst in the NL. By comparison, he made 3 errors in 168 chances in 2009, and he has a career .981 FP (.987 in 2009).
Morgan's range also seems to be a bit less this year: his range factor per 9 (RF/9: number of outs made in the field per 9 innings played) is 2.51, slightly below league-average (2.55) and in the middle of pack among CF. However, Nyjer is usually well above average in terms of RF/9: career he's 3.07 (compared to 2.61 league avg), and he was 3.21 in 2009 (compared to 2.60 league average). Why isn't Nyjer making more outs in CF? Is the Rizzo model of groundballing starters robbing him of chances? I decided to break out RF/9 for IF positions and OF positions, and compare 2009 and 2010 for the Nats (League avg in parens):
| 2009 | 2010 | |
| IF RF/9 | 30.95 (30.65) | 31.32 (31.15) |
| OF RF/9 | 7.05 (6.61) | 7.03 (6.26) |
Well, that doesn't seem to be the answer--it looks like the OF is making more outs compared to league average in 2010 than it was in 2009 (note that RF measures putouts + assists, so we're double-counting some outs). (As a side note, the Nats being above-league-average in both IF and OF RF is because they have fewer strikeouts than league average. A K counts as a PO, but most IF plays count as a PO+A, resulting in a higher team-total RF.) Okay, are pitchers somehow not squaring up on the ball, and always pulling it or going the other way to the OF? Again, splitting up RF/9 by OF position and year (with league-average in parens):
| 2009 | 2010 | |
| RF RF/9 | 2.21 (2.08) | 2.26 (2.00) |
| CF RF/9 | 2.84 (2.60) | 2.61 (2.55) |
| LF RF/9 | 2.00 (1.93) | 2.16 (1.71) |
Huh--looks like more balls are getting hit to the corners (or at least fielded there). LF, especially, is making more outs compared to league average in 2010 than in 2009, while CF is making fewer. Some of this might be early-season statistical fluctuation: six more POs or assists in CF (above the 81 to date), and the CF RF/9 would be up around 2.8.
Finally, let's look at a semi-advanced statistic, balls in zone (BIZ) and out of zone (OOZ). These are halfway to the advanced metrics: the number of balls hit into a player's zone (BIZ), the number of those balls he makes a play on, and the number of plays he makes outside of his assigned zone (OOZ). We're not trying to convert these into runs saved/lost, though, just looking at how he's doing on the raw numbers (from fangraphs). I've got Morgan's BIZ per 9 innings (to show how many chances he's getting), revised zone rating (RZR--number of BIZ that he made plays on), and his OOZ plays per 9 innings from 2009 and 2010 (league average in parens):
| 2009 | 2010 | |
| BIZ/9 | 2.26 (2.21) | 2.20 (2.01) |
| RZR | .957(.936) | .839 (.912) |
| OOZ/9 | 0.92 (0.63) | 0.60 (0.63) |
Nyjer is getting chances at a higher-than-league-average rate. However, he's not converting them: his RZR is lowest in the league. He's also not making as many out-of-zone plays; he made them at a 50% higher rate last season. It would take one more OOZ play to get him up to league average (he has 17 so far this year), but 8 to get him up to last year's rate. Likewise, he would have to have made 4-5 more plays (on top his 52 thusfar) to get up to a league-average RZR. It's still early. A full season in CF should generate around 300 BIZ (he has 62 so far), so it's certainly possible to end up with something more in line with 2009.
What have we learned? Well, the advanced stats agree: Nyjer is fielding well below his career numbers. The less-advanced stats also agree: Nyjer has made more errors and fewer outs than his career rates. We're early enough that all that may have been skewed by 3-6 bad plays, but Plush will need to make a lot of good plays going forward to get up to his career stats. Keep an eye on center, and keep your fingers crossed. Maybe all of the misplays came early...