Kevin Towers is a confident, talkative man. He’ll tell you what he’s thinking about, and he’ll tell you what he’s doing. There aren’t many anonymous leaks that come out of the Diamondbacks organization because Towers doesn’t exactly keep many secrets — even when he’s actively negotiating. Towers has spent much of this offseason talking about how badly he wanted to acquire a No. 1-type starting pitcher. He was in on Masahiro Tanaka; he’s been in on David Price. He admitted he wanted to make a significant splash. Just the other day Arizona signed Bronson Arroyo for two years and $23.5 million. Or three years and $30 million. The bigger point is that Arizona signed Bronson Arroyo, and now they’re finished.

Arroyo, of course, is no one’s idea of an ace. Most simply, the best pitchers get strikeouts, limit walks and limit dingers. Arroyo does one of those things. He’s 37 in a couple of weeks, meaning he’s basically 37 now. There’s little sexiness with this acquisition, and Towers would tell you he knows he didn’t get a No. 1. Still, Arroyo does have something going in his favor. It’s just a matter of how much you believe in it.

Well, I suppose Arroyo has two things going in his favor. One is that, so far, he’s been extraordinarily durable. In nine straight years, he’s made at least 32 starts. He’s drawn not-inaccurate comparisons to Livan Hernandez. His injury history is enough to make you chuckle: There’s a bit of back soreness, there’s a bit of leg soreness, there’s carpal tunnel, there’s mono and there are four contusions from batted balls. Arroyo’s been the image of dependability, and people credit his work ethic and his smooth, controlled pitching style.

Now, that’s meaningful. But it’s only so meaningful. Hernandez never got hurt. Dan Haren has begun to have a few problems. Jon Garland went straight from reliable to shoulder surgery. You can even point to Roy Halladay. There’s no such thing as an automatic 200 innings. Absolutely, Arroyo has a lower injury risk than Erik Bedard. But he still has some kind of injury risk because he’s still throwing 3,000 pitches a season, and then some.

The other thing Arroyo has going for him are his actual results. The past five seasons, 141 starters have thrown at least 400 innings. Right there, you know this pool is selective for starters decent enough to stick around. In WAR/200 innings, Arroyo ranks in the bottom 10, at 0.9. He’s in the company of guys like Barry Zito and Nick Blackburn and Kevin Correia. In RA9-WAR/200 innings, however, Arroyo ranks 68th — middle of the pack — at 2.6. The difference between those two numbers is 1.7, and that difference is third-greatest over the span, behind Clay Buchholz and Jeremy Hellickson. In short, Arroyo’s been beating his peripherals.

On our leaderboards, FDP-Wins is the difference between RA9-WAR and WAR. Between 2009 and 2013, Arroyo led baseball in FDP-Wins, and he led by almost two over Jered Weaver. Arroyo even beat his own peripherals in his disastrous 2011 campaign. That year, he was worth -0.3 RA9-wins, but he was worth -1.5 FIP-wins. If you look only at Arroyo’s walks, strikeouts and dingers, you see a guy who might be worth a few million on a one-year contract. If you look at the rest, you see a guy who’s better than that.

This is always such a nervous, uncomfortable thing because we never know quite how much stock to put in a guy’s ability to beat his FIP. Arroyo routinely posts better-than-average BABIP marks. He also pitches around the edges, and this implies worse-than-average quality of contact. But then, there are all of the home runs, which Arroyo allows, and which he will forever allow. It’s easy to see how Arroyo could be more deceptive than most, but again, the homers, and the overall contact rate. The true Bronson Arroyo almost has to be somewhere in the middle.

Between 2008 and 2012, the big-league leaders in FDP-Wins were Tim Hudson, Jeremy Hellickson, Matt Cain, Bronson Arroyo and Jered Weaver. In 2013, Hudson undershot his peripherals. Hellickson did, too, by quite a lot. Cain was right around even. Arroyo was Arroyo. Weaver posted an FDP of 0.9. There’s some ability here, but it’s hard to separate from all that noise, and this is why the Diamondbacks are taking a gamble. The contract comes with limited upside, and while it’s not bad, there are more ways for it to go wrong than right.

Towers did well in addressing the need for depth. He recognized the Diamondbacks would probably need more than five starters, especially given their rotation includes Brandon McCarthy, and that Archie Bradley is the only helpful guy on the horizon. Granted, this was an issue partly of Towers’ own making. But while there might not be an enormous difference between Randall Delgado and Arroyo, Arizona’s probably going to need them both. Delgado will open out of the bullpen, but he’ll start some games unless the team gets a whole lot of good luck.

Arroyo probably makes the Diamondbacks better. It depends on how much you believe in his runs-results. And while pitching in Arizona won’t do him many favors, given his style, he is coming from Cincinnati. The contract, also, isn’t potentially devastating in any way, and you can at least count on Arroyo to pound the zone and get plenty of called strikes. Yet what one has to wonder is whether Towers could’ve spent better than this. Arroyo got two years, guaranteed, at $23.5 million. Paul Maholm got a guaranteed one year for $1.5 million, plus incentives. Maholm knows he might end up pitching out of the bullpen. The past three years, Maholm has Arroyo beat easily in WAR, and they’re even in RA9-WAR. Jason Hammel wound up with a cheap one-year contract. Dan Haren got half of Arroyo’s contract. Scott Baker got a minor-league contract. Shaun Marcum got a minor-league contract. Arroyo got Tim Hudson money, but Hudson seems like the safer gamble.

Arroyo’s deal looks like a contract with significant downside. Arroyo seems like he could come apart at any moment. He seems like he’s pitching with just about the narrowest margin of error. He’s also allowed 174 runs in his last 404 innings, pitching half the time in a hitter-friendly ballpark with utterly underwhelming stuff. In the end, this is a two-year bet on continuity of a very particular and unreliable kind.