Athletics offseason: Is Billy Beane now targeting pitchers with low home run rates?

Last week, a tweet from a fellow Oakland Athletics fan caught my eye that got me to thinking.

@jfkooAN @AlexHallAN Alvarez didn't allow a HR in the minors last season, Graveman/Bassitt allowed two, and Hahn only allowed four (in MLB).

— Matt Cresta (@MattCresta) February 1, 2015

Sufficiently intrigued, I took a look at the new pitchers acquired by the A's this winter to see if there was indeed a homer-suppressing theme.

- R.J. Alvarez has allowed two homers in 129⅓ career minor league innings, and he didn't allow a single dinger last year in the Texas League or in eight MLB innings. In 2013, he kept the ball in the park in the California League, where offense is so strong that we often temper excitement on our own Stockton Ports hitting prospects until they achieve success at higher levels.

- Chris Bassitt was last seen throwing 13 dominant, homer-free innings in the Arizona Fall League, and before that he tossed 29⅔ MLB frames for the White Sox (including five starts) without anyone leaving the yard. Before that, he allowed only two dingers in six Double-A starts. All told, he's given up 20 long balls in 357⅓ professional innings, and he's been markedly better than average the last two years in the Double-A Southern League.

- Tyler Clippard gives up a normal number of homers per nine innings (HR/9), but that's because he's an extreme flyball pitcher. By extreme, I mean that he ranked 11th among all pitchers with at least 50 innings in flyball rate last year; his career average (55.9%) would have ranked third in 2014. Relatively speaking, though, he's actually quite good at keeping his flies in the park; his homer-per-fly-ball rate (HR/FB) was far better than league average last season and his career rate is strong. He'll always give up lots of flies, and some will find the seats, but many more will die in the infield and the Coliseum's extra foul territory could be the best thing that ever happens to him.

- Kendall Graveman, on the other hand, is an extreme groundball pitcher. By nature, groundball pitchers don't give up a lot of homers, because it's nigh impossible to homer on a grounder. On average, MLB pitchers induced grounders 44.8 percent of the time last year. Graveman was closer to 60 percent, and in his brief trial in Toronto he reached 64.3 percent (9-of-14 batted balls were on the ground). Therefore, it's no surprise that only two batters went yard on him in 172 innings over five levels last year. Some batters will inevitably make hard contact off of him, but it's just really tough to hit the ball high enough to homer off of Graveman.

- Jesse Hahn allowed only two homers in 163⅓ career minor league innings, and then he served up only four more in 73⅓ for the Padres. Before you write that off as a Petco Park effect, note that Hahn's MLB workload was split evenly between home and road and only one of those four homers came on the road. Hahn is a groundball pitcher, so that helps explain his low-dinger profile, but when he does get fly balls he still keeps them in the park at a better-than-average rate.

- Sean Nolin isn't quite as impressive as the previous guys on the list, but he did hold the International League to a lower homer rate than the overall average (six in 87 innings). It wasn't a fluke, either, as he matched his career minor league rate (0.6 HR/9). He's allowed homers in both of his MLB outings, spanning only 2⅓ innings, but overall in his career he's kept them at a reasonably low level.

So, that's six new pitchers. Four of them appear to have a serious knack for keeping the ball in the park -- two groundball specialists (Graveman, Hahn), two hard throwers (Alvarez, Bassitt). The other two aren't much better than average at homer suppression, but Clippard is good at reining in the huge volume of fly balls he allows (and could be even better in the Coliseum) while Nolin is at least starting his MLB career on the right side of average. If you're looking for one theme connecting six otherwise different hurlers, there's one for you. Add in quiet pickups Taylor Thompson (nine HR in 309⅓ career minor league innings) and Eury De La Rosa (0.6 HR/9 in minor league career) for a couple more examples.

Last year, the headline was that Beane was targeting flyball hitters. The theory went that groundball pitchers were strongly in vogue, and flyball hitters, who are generally better than groundball hitters anyway since they can hit for more power, are particularly good at exploiting groundball pitchers. In the past he has famously targeted other things, like high OBPs in the early 2000s or strong defense around 2010. Perhaps, now that his lineup projects to have a bit less power than the past few years, he wants to level the playing field by keeping his opponents from doing too much slugging.

Teams have gone after high-strikeout guys, and teams have gone after control artists with low walk rates. But the guys who have consistently low homer rates are the ones who are always mentioned as more isolated cases, usually in conversations about beating FIP. Maybe Beane is taking a crack at more fully exploiting the final area of fielding-independent pitching at the team-wide level. The pitchers aren't all necessarily amazing overall, but if they are each good at this one particular thing then you can turn every opponent into the Royals but without all the singles and steals -- punchless, but unaccustomed to having to rely on other methods of scoring.

How does the rest of the team fit into this pattern? Sonny Gray has always been noted for his low dinger allowance, since he gets lots of grounders and strikeouts. Ryan Cook has been brilliant, with only nine long balls in around 200 innings. Fernando Abad and Sean Doolittle don't give up a lot of souvenirs. Dan Otero is one of the more extreme groundball pitchers in baseball, and he's only served up four bombs in 138 MLB innings; Eric O'Flaherty is of a similar mold. Scott Kazmir, Drew Pomeranz and Jesse Chavez don't really fit the theme, though -- Kazmir and Chavez only recently stopped giving up homers by the bushel, and Pomeranz's track record in this area has been spotty and has been confounded by Colorado's altitude effects.

Of course, Kazmir is gone after this year, and Pom and Chavez aren't even locks for the 2015 rotation. If Beane is indeed targeting low-homer pitchers, then maybe he's starting with this new wave of acquisitions (plus Sonny and the top incumbent relievers) as a long-term dinger-free core. Or maybe he's discovered that low homer rates are a more important indicator of a young pitcher's future success than previously realized, either in terms of finding guys whose ceilings are being underestimated or whose relatively high floors make them safer gambles. There could be some other reason we haven't even thought of, or there could be no reason at all. For the moment, all we have are numbers and the knowledge that Beane is always up to something new.

Maybe this is another one of Beane's strategies, or maybe it's a big coincidence and the larger truth is just that good pitchers don't give up lots of homers. What do you think? Is there something to this, or are we just grasping at air, trying to connect dots that aren't there after a long and brutal offseason? Let's duke it out in the comments!