Gregor Blanco is certainly a buy-low candidate. He was below replacement-level in 2016, but over the four previous years in San Francisco, had averaged 1.7 bWAR and 2.3 fWAR. He turned 33 on Christmas Eve, so hopefully won’t be falling off a cliff yet. His problems last season were mostly at the plate, where his OPS dropped over 160 points from the 2015 figure, as Blanco posted a line of .224/.309/.311.
The good news is, a nagging shoulder injury may have been responsible, manager Bruce Bochy saying in August when Gregor went on the DL , "I think [Blanco's injury] did start gradually and has been getting worse and worse to the point where he couldn't get a good swing off." A lot of the decline was also due to BABIP, almost sixty points down compared to 2015. If this returns to at or near his career figure of .320 this season, a bounceback in offensive numbers would likely follow. Blanco’s K-, walk- and line-drive rates were all close to his career figures, so there doesn’t appear to have been any fundamental change in his approach.
Speaking of which, worth noting Blanco has a better than MLB average walk-rate. Indeed, his career figure of 11.1% would trail only Paul Goldschmidt among regular Diamondbacks last year, and even the lower 2016 figure of 10.6% would drop him additionally behind just Jake Lamb. Could this be a trademark of the Mike Hazen era? While two swallows might be a bit early to proclaim the arrival of summer, it is perhaps worth noting the trend, since with Chris Iannetta, that's now consecutive free-agent signings for Arizona with good plate discipline.
It certainly appears that whoever the fourth outfielder ends up being for the 2017 Diamondbacks, they will be a southpaw. For all three of the leading candidates to this point are lefties, Blanco joining Jeremy Hazelbaker and Socrates Brito. This one looks like it will be a spring battle, though I’m always a bit nervous about that, because spring stats are not necessarily any guide to regular season results. Sure, Jean Segura led all regular hitters last pre-season for Arizona by batting .469. But Nick Ahmed and Rickie Weeks Jr. both also hit better than .430. Once the meaningful games started? Not so much.
Which one gets the nod, may also depend on how Torey Lovullo intends to use his fourth outfielder, because they offer markedly different qualities [though small sample size makes some of these deserving of an asterisk] Hazelbaker has better power, but also hits left-handed pitching a lot worse, with an OPS 237 points lower at .585. So if you’re looking for home-runs and think you can shepherd him away from facing LHP, he might be the man. Blanco’s splits are a lot more even - only 30 OPS points worse against lefties over his career - so he would perhaps offer more "everyday" potential, rather than as a late-inning weapon off the bench.
On the other hand, Brito might well be the best choice if the team is looking for a late-inning defensive replacement (coughTomascough). Both Hazelbaker and Blanco are graded poorly by the defensive metrics overall as outfielders, though in the latter’s case he seems consistently a good deal better in left field than center or right, and is generally a plus there, even over the last couple of years, when his numbers elsewhere have declined. But if we want someone who can perhaps give A.J. Pollock and his elbow the occasional day off, Brito would likely represent the alternative that would offer the smallest drop in defense there.
It’s somewhat amusing that the fifth outfielder spot appears right now to be more certain for the D-backs this year than the fourth outfielder spot. Chris Herrmann’s positional flexibility, including his ability to be a third catcher, makes him a pretty good 25th man. But you can make a case for any of Blanco, Brito and Hazelbaker to occupy the slot ahead of him. Seems like a good excuse for a poll...