Catcher defense has not been a major concern for the Orioles ever since Matt Wieters was called up in 2009. Wieters has a reputation as a gold glove catcher, which he has won twice in 2011 and 2012, and the advanced metrics have backed that up. This season, for the first time since 2009, the O's are looking at an extended stretch with someone other than Wieters behind the plate, with Wieters potentially undergoing season-ending elbow surgery. The group that is taking up his playing time, namely Steve Clevenger, Nick Hundley and Caleb Joseph, has predictably struggled at the plate. Are they making up for their lack of production at the plate from behind the plate?
First, let's examine Wieters's numbers from the past. There are few aspects of catcher defense that I will consider here, namely catching base-stealers, blocking pitches and framing pitches. Base-stealing data is taken from Baseball-Reference, while pitch blocking and pitch framing data are taken from Baseball Prospectus. Wieters has been above average in terms of catching base-stealers for every season except his first. Over his career, he has caught 33% of those attempting a steal, against the league average rate of 27%. This, by Defensive Runs Saved (DRS) calculation, is worth 15 runs above average for his career. Wieters also rated positively in terms of pitch framing. Last season was the only season where Wieters has cost his pitchers strikes. Wieters does not rank particularly close to the framing elite such as Jose Molina, but it has been worth about 12 runs (by number of extra strikes) above average for the O's in total. Where Wieters has really shined behind the plate is blocking pitches. He has saved more than 10 wild pitches/ passed balls in every season and ranks among the top 3 in the league in this category every year. Unfortunately, the spread in this skill is much smaller, so Wieters's elite skill has only saved the O's about 22 runs over his career.
How has Wieters's replacement crew fared in these categories? In terms of catching stolen base attempts, Joseph has been superb in nailing 44% of the base-stealers, whle Clevenger's and Hundley's CS% both hover around 15%. The sample has been small, so we should not read too much into the high CS% of Joseph nor the low numbers posted by Clevenger and Hundley.
In terms of pitch blocking, all three have been right about average in the league. The three have excelled at framing pitches so far this season, earning 40 more strikes for the O's pitching staff in one quarter of a season of playing time. (Assuming Hundley's number is evenly spread out over his time with the Padres and the O's) This number is higher than Wieters has ever put up in an entire season. (Just a side note, Hundley has a disastrous history in pitch framing, It just hasn't shown up yet.) This has saved the O's an estimated 6 runs above average according to Baseball Prospectus. Prorating this to a full season would put the O's among the tops in the league. In 2013, 24 runs above average would have placed fourth in the league, behind the Brewers, Rays and Yankees.
If Joseph, Clevenger and Hundley continue their pitch framing pace, they may not completely make up for the loss of Wieters, but they at least minimize the impact of Wieters's absence.