Let's get this out of the way first, for the pessimists in the house: there is a reason the headline says "might know," and not "absolutely know." We can theorize about what Daniel Bard would do as a starting pitcher, based on his repertoire, past history of relief-to-starter conversions (and vice versa), and his performance in the majors, but we don't know for sure. What this is meant to do is provide some context for what we might be able to expect, should the Red Sox go ahead with a plan that continues to be cited as a possibility.
That paragraph isn't meant to totally dismiss those who aren't optimistic about Bard as a starter, either. There are reasons to like and dislike this idea, and the plan is to explore those.
Daniel Bard, Minor League Starter: Bard was drafted as a starter back in 2006 as the #28 pick in the draft. He made his professional debut the next season, as a starting pitcher, in a year that he and anyone who watched it would like to forget. Bard made 22 starts between Single-A Greenville and High-A Lancaster, posting a combined ERA of 7.08, with 47 strikeouts against 78 walks in just 75 innings pitched.
Granted, Lancaster, a high-offense park, can shoulder some of the blame, but this was mostly on Bard. His mechanics were completely different then, and obviously not working for him against professional hitters. These mechanics were not his own doing, either, As Brian MacPherson mentioned in November: the Red Sox toyed with his mechanics after drafting him.
Boston switched Bard to relief following his disaster debut, and he switched back to his old mechanics during his time in the Hawaiian Winter League, and he was no longer throwing 90-93 with poor location. Instead, he was destroying the opposition, and spent just one more full year in the minors before coming to the majors, thanks to a 1.51 ERA, 77-2/3 innings, 12.4 K/9, and 3.4 K/BB. He has been Boston's second-best reliever since, even pitching as the better of the Jonathan Papelbon/Bard duo at times in his two-and-a-half years with the Red Sox.
There is no guarantee that Bard also would have succeeded as a starter with his old mechanics, but at the same time, we don't know that he would have failed, either. His stuff worked completely differently, and he rediscovered the strike zone as well as his velocity once he went back to familiar mechanical territory. Some of the bump in velocity had to do with the one-inning stints, but command and control are not affected the same way.
The Rule of 17: Tom Tango knows his statistical analysis, and one of the things that has been discovered in his many endeavors is learning what happens when a starter becomes a reliever, or a reliever becomes a starter. "The Rule of 17" is the result of this research, named because of how oddly often that number shows up in this matter.
The strikeout-per-plate appearance (K/PA) of a pitcher goes up 17 percent as a reliever, after starting. Batting average on balls in play tends to drop an average of 17 points out of the bullpen. Home runs (relative to contact) drop 17 percent out of the bullpen as well. Walk rate, though? That remains flat, as control and command might improve somewhat thanks to shedding a fringe pitch, but not to a degree where the rate of free passes allowed is going to drop significantly.
Looking at Bard's Red Sox career as a reliever through the lens of 17 yields promising results: his strikeout rate would fall from 26.7 to 22.2 percent, his home run rate would rise from 3.2 percent of balls in play to 3.7 percent, and his BABIP would sit at roughly .263 rather than .246. The league average strikeout rate by percentage was 18.6 in 2011; home runs as a percentage of balls in play, 3.4 percent; BABIP, .291. He might give up an extra home run or two than average, but other than that, those numbers come out looking like he would make a successful starter.
But Is He Even Better In The Pen: Nate Silver researched the idea of whether an individual pitcher is more valuable out of the bullpen or the rotation years ago, for a case you are all familiar with. Jonathan Papelbon was a starter in the minors who became the Red Sox' shutdown closer, and for a time, there were questions about which direction his career would head. (This was before it was widely-known that Papelbon's shoulder required a regimented throwing program that has a lot to do with his remaining in baseball to begin with.)
Silver basically wanted to find just how good Papelbon would have to be as a reliever to justify keeping him out of the rotation:
Throw all of these assumptions into a blender, and we find that a 2.00 ERA closer is roughly as valuable as a 3.69 ERA, 200-inning starting pitcher.
Papelbon, at his best, was a closer capable of legitimate 2.00 ERA or better performances. If his shoulder was capable of handling a starter's workload, there was an argument to be made to keep him in the bullpen anyway. But what about someone like Bard, who is a great reliever in his own right, but not necessarily a historically-good one, like Papelbon was in Boston?
Bard's career ERA is 2.88, after 197 appearances and 192 games in Boston. That's impressive, but it's not as good as Papelbon, who was at 2.33, and pitched during a few seasons with higher offensive levels, too. ERA not your metric of choice? Papelbon's FIP in Boston was 2.60, Bard's, 3.22. There is a clear level of difference between the two, even if both are pitchers that every team in baseball would like to have -- as Silver wrote back in 2006, Papelbon isn't your typical relief pitcher, as he's in the "95th percentile" for relievers, historically. Time has proven this sentiment to be correct.
This means Bard isn't at the level where he is so ridiculously good out of the bullpen that the idea of moving him becomes silly out of hand. Rather, he's at the level where, because he is so good as a reliever, it's worth exploring whether he can be a useful starting pitcher, as well.
Silver found that a pitcher's ERA typically improved by 25 percent after leaving the rotation for the pen. The opposite works as well, so Bard's 2.88 ERA as a reliever translates to a 3.60 ERA as a starter. That isn't every reliever/starter conversion, of course -- you get relievers who just don't work because they aren't good pitchers in any role, or ones who transcend the expected results, like Papelbon.
It's Not All About Numbers, Though: The Rule of 17 and Silver's excellent research are guides that help paint a picture of what a pitcher would look like in one role or another, but there is more to baseball than numbers. Does Bard have the stuff and the repertoire to succeed in a role where he will be expected to go through a lineup multiple times?
Bard has averaged 97.4 miles per hour on his fastball in the majors, and while that is likely to dip by 1-2 mph as a starter, that is still an intimidating heater. It's not like he would just touch 95 as a starter -- he would sit there. His slider is his big out pitch, the one he has thrown 20 percent of the time in his career (closer to a quarter of the time in the recent past), and the one that misses by far the most bats. He has a change-up, and it has been effective for him (swing-and-misses on 16 percent of change-ups; league average is 12 percent), but given he has used it less than five percent of the time, one wonders if its success is part, in due, to its lack of use. The surprise factor of the pitch has worked in Bard's favor, but should be start, he would likely need to utilize it more often. Whether that would be successful or not is something we will have to see to know for sure.
There are relievers who have converted to starting who have succeeded with less stuff than Bard has, of course. Alexi Ogando is a two-pitch pitcher, and he had a fine first year out of the rotation with Texas in 2011. Justin Masterson basically has one pitch -- his fastball -- but it is so heavy that hits are hard to come by, and when struck, it often ends up on the ground. That doesn't necessarily mean Bard would work as a two-pitch starter, either. It's much more likely he will need that effective off-speed pitch for when he is facing a lineup the third time through.
Overall, though, those two are probably an apt point of comparison for expectations of what Bard could do as a starter. Neither are total game-changers, but they have more value as average-to-above starters than they would as relievers, even if they would be high-quality bullpen arms. The more innings a good pitcher can throw, the more valuable he becomes -- not everyone needs to be Jon Lester to be a successful starter.
One other thing Bard might have in common with Ogando, though, is his limits for innings. In the first year of this experiment, at least, it's unlikely Bard would be able to throw anywhere near 200 innings. C.J. Wilson, who has done that in his two years as a starter, is more exception than rule in this regard. Of course, you can't work up his innings until you start using him out of the rotation, either, so putting it off another year doesn't make a conversion any simpler in the future.
With the expensive and lacking starter's market, if Bard can be anywhere near as good as his numbers in relief, translated through Tango's and Silver's work, make him look like he can be, then the Red Sox should absolutely explore the idea of Daniel Bard: Starting Pitcher. It's not necessarily a guarantee to succeed, by any means -- maybe his change-up doesn't work well enough as a starter, or he just doesn't have the durability to make it work -- but should Bard as a starter work, giving the Red Sox the fourth starter they have been trying to acquire through various means for years, then it would be a far better use of his arm than another 65 frames out of the bullpen. The reward is worth the risk; the worst thing that happens is we answer a question about Bard, and what role he is actually a better fit in.