Re-Evaluating The Defense Of Matt Wieters And Caleb Joseph

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For the second straight season, the Orioles will have two starting catchers. Matt Wieters, who annoyingly returned to the team for 2016, will join third-year professional Caleb Joseph behind the dish. While both players have inconsistent (at best) offensive histories, they've generally carried above-average reputations when it comes to defense. But just how good are they in that regard?

Thanks to Baseball Prospectus, we have a few new metrics with which to appraise them. On Tuesday, they debuted/expanded four catcher defense metrics: Swipe Rate Above Average, or SRAA; Takeoff Rate Above Average, or TRAA; Errant Pitches Above Average, or EPAA; and Called Strikes Above Average, or CSAA. These rate statistics — which we'll delve into momentarily — combine to form the new FRAA.

Does BP differ from Baseball-Reference and FanGraphs when looking at Wieters and Joseph? It certainly does, and fairly significantly:

Player	BP Career Runs	B-R Career Runs	FG Career Runs
Matt Wieters	30.0	10	34.9
Caleb Joseph	27.1	20	4.6

Wieters has had a large gap between his B-R and FG defensive profiles for some time now; BP manages to split the difference. Perhaps more importantly — since he should stick around for longer — Joseph comes out much further ahead in BP's eyes. This explains why, in 630 career plate appearances (about a full season's worth), Joseph's 4.0 WARP dwarfs his 3.4 rWAR and 2.2 fWAR. Why do the systems diverge like this? Let's dive into the metrics behind them.

There's first the most obvious component of catcher defense: throwing out attempted base stealers. For this, both B-R and FG rely on DRS's stolen-base component, called rSB. BP's new metrics split up throwing in terms of holding runners on base and cutting them down when they try to go, for which TRAA and SRAA respectively account. The runs from these go into "Throwing Runs". Both Wieters and Joseph earn lesser ratings from BP than they do from DRS:

Player	rSB (B-R/FG)	Throwing Runs (BP)
Matt Wieters	15	6.5
Caleb Joseph	5	2.0

With that said, the disparity between rSB and Throwing Runs doesn't just apply to the Baltimore backstops. The latter metric takes a more conservative view to most catchers — on both ends of the spectrum. Since 2003, when DRS came into existence, Yadier Molina leads the majors with 58 rSB runs, compared to just 28.5 Throwing Runs. His brother Jose, finishing second with 35 rSB runs*, owns only 11.5 Throwing Runs in that span. Meanwhile, last-place Jason Varitek (-26 rSB) and penultimate John Buck (-23 rSB) have respective Throwing Run totals of -7.7 and -3.0.

*Across about half as many innings. Molina's pretty good at that whole defense thing.

Why do the BP metrics weight catcher arms less heavily? As first postulated by Max Weinstein, pitchers have a much greater effect on the running game than catchers do. SRAA adjusts for the skill of the pitcher, as well of the skill of the runner, to better isolate the catcher's contributions. TRAA focuses mainly on the pitcher, who can intimidate runners to a much greater degree than catchers can. In other words, both recognize the limited role of catchers and rate them accordingly.

For an illustration of this, look at the 2015 Orioles. Joseph threw out 32.7 percent of runners, allowing 66.6 attempts per 1,000 innings. However, that fluctuated rapidly depending on his battery mate. With Joseph behind the plate, Ubaldo Jimenez gave up a 16.7 percent caught-stealing rate on 124.7 tries every 1,000 frames, while 50.0 percent of runners (taking off 25.9 times on a per-1,000 inning basis) succeeded against Chris Tillman. Even talented arms such as Joseph and Wieters — who sees a similar dropoff from Jimenez to Tillman — will suffer when their pitcher doesn't pull his weight.

Catcher defense doesn't end with throwing, of course. Preventing both wild pitches and passed balls will set the elite apart from the scrubs, which is where FG's Runs from Passed Pitches (RPP) and BP's EPAA (measured in Blocking Runs) come into play. For one of the two Orioles, we witness the same pessimism from the latter that we saw from Throwing Runs:

Player	RPP (FG)	Blocking Runs (BP)
Matt Wieters	20.0	7.9
Caleb Joseph	-0.6	-0.1

Two caveats: B-R doesn't measure blocked pitches, and these figures don't include 2015, for which RPP data don't exist.

This, too, affects other catchers. Yadier, the first-place catcher by RPP? He accrued 28.5 of those runs and 9.4 Blocking Runs from 2008 to 2014. Wilin Rosario, the last-place catcher by RPP? He cost his clubs 21.7 runs in that metric, but his Blocking Runs sit at a more palatable -9.4. So Wieters has company in his dropoff.

As with the moderate SRAA/TRAA opinions, this happens because of EPAA's different methodology. Its creator Jonathan Judge explained how EPAA avoids RPP's main pitfall: Wild pitches and passed balls, as we'd suspect, are not equal. Although the former occur due to a number of factors, catchers almost always bear the responsibility for the latter. The model that RPP utilizes to predict passed balls — as well as the similar model that EPAA had previously used — suffered from this flaw, which caused volatility and inaccuracy. The new version of EPAA corrects for this, as well as for the more minor problems with wild pitches (which pitchers control a little more than we had originally thought).

Passed balls have never plagued Wieters — for his career, he's allowed three every 1,000 innings, much lower than the MLB average of 7.4/1000 in that span. He doesn't fare quite as well when it comes to wild pitches, where his 24.8/1,000 rate comes a bit closer to the major-league clip of 38.0/1000. This, along with the shift from wild pitches, helps to bring his blocking numbers down a bit.

What more constitutes catcher defense, aside from gunning down opponents and snaring balls in the dirt? The newly-discovered (by sabermetrics, at least) field of framing. Since neither B-R nor FG yet incorporate receiving into their catcher defense, BP — which converts CSAA into Framing Runs — stands apart here. That's a pretty critical oversight on the part of the former two, because man, framing makes a huge difference:

Player	Framing Runs
Matt Wieters	13.6
Caleb Joseph	23.1

For Wieters, a mediocre receiver, the addition here still upgrades him by more than a win. His superior colleague Joseph sees a two-win jump, and in far less playing time. Framing compensates for the decreased importance of throwing and blocking, a development that probably thrills both men (if they care about advanced statistics).

We've long known about Joseph's skill when it comes to framing. Jon praised it in 2014, a year in which Joseph's CSAA ranked seventh in baseball among 33 qualified catchers. He didn't miss a beat in 2015, either, coming in at eighth out of the same sample size. Wieters, on the other hand, falls short of expectations — primarily because of a recent decline. In his first four seasons, he piled up 27.6 runs from fooling umpires; since then, they've turned the tables, and he's cost Baltimore 13.7 runs. Even before his injury-blemished 2014/2015, he had declined, posting -8.1 Framing Runs in 2013. Whatever the cause, it would seem that Wieters can't frame like he used to, or like Joseph can currently.

Broadly, the takeaways here are threefold.

1. Throwing matters less for catchers than you might think, because pitchers have to hold the runners in place.
2. Blocking matters a bit less for catchers than you might think, because pitchers have to throw decent pitches; however, passed balls come down almost entirely to the catcher.
3. Framing matters much more for catchers than you might think — and matters more than anything else.

In terms of the present Oriole catchers, we now have a better idea of their skills. Wieters has displayed respectable throwing and blocking ability, but those may not matter given his poor framing ability. On the flipside, Joseph possesses a mediocre arm, doesn't always keep the ball in front of him, and receives it spectacularly. Not only does Joseph's latter characteristic negate the former two, it elevates him past Wieters in the defensive pecking order. After 2016, when Wieters hopefully signs elsewhere, the Orioles should have a solid backstop for the next few years. (And even if Joseph declines, rising star Chance Sisco could take his place.) Whatever the Orioles do, these new metrics will grant us a better ability to conclusively evaluate the defense of Baltimore catchers.