Stolen Bases: Is It Miller or Is It Stock?

With opponent stolen bases mounting, is it the Quad Cities River Bandits pitcher Shelby Miller or his catcher Robert Stock who should be scrutinized?

A couple of weeks ago, as the Twitterverse was going ga-ga over a start by St. Louis Cardinals pitching prospect Shelby Miller, I dared to offer a contrary view. One of my counterpoints to the right-hander's customary five-inning outing that evening was that the Quad Cities River Bandits' opponents were a perfect 4-for-4 in stolen bases against Miller and his batterymate, Robert Stock.

One very thought-provoking reply went something like this: "Is it Miller or is it Stock?"

I didn't reply – until now.

While Miller, the Cardinals first-round pick last year, has received a high level of scrutiny this season, the 2010 struggles of the club's second-rounder, Stock, have received a relatively small amount of attention.

At the plate, here are Stock's batting averages by month, starting in April: .213, .214, .200, .192. In August, he has improved to .286, bringing his full-season mark up to .216. Stock has just 25 RBI in 299 plate appearances and has yet to hit a home run in 2010.

The focus of this article isn't Stock's offensive woes, however. I dug into the stats of the River Bandits' catchers this season to see what I might learn, taking the period from opening day through August 11, Miller's most recent start.

Stock (pictured) had 67 starts behind the plate, Ivan Castro chipped in 42 and Roberto Espinoza four. Collectively, the group has had a 32.5 percent success rate throwing out opposing base stealers this season, with Stock below the team average at 28.3 percent and the other two above.

While I don't have innings caught for each, taking a rough measurement of steal attempts per start indicates a slightly-higher number of attempts when Stock is the starting catcher, but the difference is not huge.

Team total Inn CS SB Att Pct Starts Att/Start
Castro 25 43 68 0.368 42 1.6
Espinoza 4 2 6 0.667 4 1.5
Stock 34 86 120 0.283 67 1.8
TOTAL 999.3 63 131 194 0.325 113 1.7

Because Stock caught 13 of Miller's 20 starts, could his numbers be skewed by his pitcher?

Here is where the story gets really interesting. In the two tables below, I have broken out the Bandits' catching stats between Miller starts and non-Miller ones.

w/Miller Inn CS SB Att Pct Starts Att/9 IP
Castro 3 7 10 0.300 5
Espinoza 1 0 1 1.000 2
Stock 4 19 23 0.174 13
TOTAL 84.3 8 26 34 0.235 20 3.6
thru 8/11
Rest of tm Inn CS SB Att Pct Starts Att/9 IP
Castro 22 36 58 0.379 37
Espinoza 3 2 5 0.600 2
Stock 30 67 97 0.309 54
TOTAL 915 55 105 160 0.344 93 1.6

What you can see is that both Castro and Stock have a markedly poorer caught stealing percent when they are catching Miller. In non-Miller games, Stock's mark of 30.9 percent isn't spectacular, but is far better than the 17.4 percent rate he has logged when he is behind the plate catching Shelby.

The telling stat is on the far right. Opposing baserunners take off against Miller to the tune of 3.6 times per nine innings on the average, compared to just 1.6 times per nine against the remainder of the River Bandits' staff.

I have only seen Miller pitch once in person since spring training, but the club's radio broadcasters have often noted how slowly he works. Perhaps Miller is trying to be mindful of the baserunners, but if so, it doesn't seem to be working.

Miller has allowed eight steals in ten attempts over his most recent three starts, totaling 15 innings. That is his worst stretch of the season in terms of running activity and opponent success.

The answer: It's mostly Miller in the soup, with a helping of Stock mixed in.

Brian Walton can be reached via email at Also catch his Cardinals commentary daily at The Cardinal Nation blog. Selected TCN content appears at Follow Brian on Twitter.

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