A brouhaha has erupted in the wake of an ESPN report that seems to implicate the Toronto Blue Jays in using some sort of relay (a now infamous "man in white") to steal signs, which would be in contravention of the rules of baseball. You'll note I say "seems to implicate," because ESPN doesn't have any sort of actual proof that the Jays have stolen signs illegally, more like rumour and conjecture; the article by Amy K. Nelson and Peter Keating is at various points subtitled "The Blue Jays deny they're stealing signs - evidence may lead to another conclusions" and "Baseball's Toronto Blue Jays under suspicion again of stealing signs at Rogers Centre."
The evidence offered essentially breaks down to anonymous player reports (seemingly from a single bullpen), statistical cherrypicking, and the extreme unusualness of the Jay's 2010 offensive season. None of these on their own are convincing, but according to ESPN when put together they mean that "every pitch to a Blue Jay in Toronto is worth watching" which is of course meaningless pablum, but which again seems intended to implicate that the Jays are doing something illegal or unethical.
So are the Blue Jays stealing signs illegally? I have no honest idea. I'm sure they are relaying pitch location from second base with runners on; plenty of teams do that, and the Jays seems to be at the forefront of that. I'm willing to acknowledge that it's within the realm of possibility that the Jays are even going farther than that - not especially likely, but not completely improbably either. Mostly though, I think it's unfortunate that ESPN decided to run with what seems like at best a highly circumstantial set of allegations that are not backed up by it's own reporting. Let's review.
The article breaks down into essentially four areas.
1. Four players on a visiting team saw a man in white who they believed was signalling whether pitches were going to be fastballs or offspeed pitches from the outfield bleachers. Subsequently, the Yankees and the Red Sox began using multiple signs with no one on base against the Jays, the most logical reason for which would be a concern for stealing signs. However, no official complaints have been lodged against the Jays.
2. The Jays hit a lot of home runs in 2010, a lot of which were at home, and they had the highest isolated power (slg - avg) since 1954.
3. Several Jays had strong home/road splits in 2010.
4. The Rogers Centre played like a massive home run park in 2010, but only for the Blue Jays and not for road teams.
Point 1 is the most convincing, but ultimately breaks down into one incident viewed by one bullpen (probably the White Sox) as well as conjecture.
Points 2 and 4 are slightly ridiculous in trying to prove the Jays steal signs. First and foremost, it's not clear what the rationale for using home run hitting as a proxy for overall hitting ability is. They clearly aren't the same thing. That the Jays got a home run boost that their opponents did not receive in 2010 is certainly interesting and worthy of additional study, but it's not clear how it relates to sign stealing. The author of the study (not included in the ESPN report) on how the Rogers Centre played, Baseball Prospectus' Colin Wyers, was not specifically examining sign stealing. I'm sure his information is correct, but it doesn't "prove" anything regarding sign stealing.
Looking at the numbers more thoroughly, problems emerge. The Jays had a .274 average on balls in play on the road in 2010, and hit 11.6% of their fly balls for home runs, a total of 107. The first two numbers are the worst and best in the Majors, respectively, and the 107 home runs put them a close second best to the Red Sox (113), with whom they lapped the field (the Twins were third with 90.) At home they led the league with 150 home runs (the Yankees were second at 115) and HR/FB% (15.5) and were dead last in average on balls in play, by a wide margin - .265, with second worst being .281. The team's wOBA at home was .346, 7th best in baseball. On the road it was... .321, t-7th best in baseball. If you're curious, the home average was .329 and the road average .312. So at home the Jays were 5.16% better than average, and on the road they were... 2.88% better than average. I can't imagine that is particularly statistically significant. The Yankees were 11% better than average at home and 5% better at home, for what it's worth. So basically the Jays hit slightly better at home than on the road, but ESPN chose to present an incomplete picture of the information that made the difference seem larger... unless anyone can tell me how stealing signs would only help hitting home runs.
The best part of the article is point 3, which lists five Blue Jays with good home-road splits (one was Yunel Escobar, with his 266 PA, real sample size appropriate to be splitting in half there guys) Two things. One, almost all players hit better at home than on the road, about 5.5% better last year, by wOBA. Two, given that we've just shown that relatively speaking, the Jays hit about as well as they did at home in 2010 as they did on the road, these numbers offer almost no additional meaning or clarity. If anything they confuse the issue.
Also apropos of nothing, Jays who hit better on the road in 2010 (numbers from BR)
Edwin Encarnacion at home .667 OPS and 7 home runs, on the road .887 and 14 home runs.
John Buck at home .772 OPS 10 home runs, road .829, 10 home runs.
Fred Lewis .730 v. .761 (4 home runs each)
To conclude, are the Jays stealing signs? Possibly, if not probably. They certainly seem to be good at relaying signs from second base, which is perfectly legal, whatever the morals. Are the Jays using a party outside the field to steal signs and relay them to hitters. Maybe. Maybe not. I would describe it as essentially unknown at this point, because the ESPN article does absolutely nothing other than to provide the uncorroborated statements of four relievers from the same team, in reference to one (maybe two incidents.) Surely if this was widespread, they could do better than that? What's most troubling is that, the statistical evidence used to back up the claim is for the most part irrelevant.
The article concludes thusly: "By themselves, these numbers are circumstantial evidence. Unsupported by data, the four players' accounts might describe a scheme of uncertain impact. And without proper context, the Yankees' decision to mask their signs could be chalked up to paranoia. But together, the numbers, the stories and the actions indicate one certainty: Every pitch to a Blue Jay in Toronto is worth watching."
Not to be unduly harsh, but that basically reads like a first year university essay - here's a bunch of stuff I said, it might be true or relevant but it's not both, and in conclusion, this may or may not be the case. Given the importance (relative, not absolute) it seems like it would have been worthwhile for ESPN to nail things down a little better..