Series preview: Arizona Diamondbacks aren't contenders, but shouldn't be overlooked

At 57-59, the Diamondbacks are essentially out of the playoff race, and some questionable recent moves suggest that their front office might not be the team to aid them in returning to the postseason. Nonetheless, they have a strong core of position players, and they're far from being helpless.

POSITION PLAYERS / HITTING: .265/.326/.408. 18.6 fWAR, third in the National League. I was a little surprised to see the Diamondbacks rated this highly, but UZR thinks Arizona's defense (led by shortstop Nick Ahmed and center fielder A.J. Pollock) is terrific.

Also, having Paul Goldschmidt (.337/.451/.575, 5.6 fWAR) and Pollock (.313/.367/.477, 5.1 fWAR) gives the Diamondbacks' lineup a gigantic head start. No other team in baseball has a pair of position players who have combined for 10.7 fWAR. There aren't many ballplayers anywhere better than Goldschmidt, and the few who have arguably been more productive this year (Bryce Harper, Mike Trout and Josh Donaldson in particular) haven't had a teammate nearly as good as Pollock. (Both the D-backs and Pollock are interested in an extension for Pollock, by the way -- getting him to sign away a couple years of free agency eligibility would probably be a good move on their part.)

The Diamondbacks' lineup doesn't start and end with its top two players, either. Another outfielder, David Peralta, has quietly had a terrific season, and the D-backs' June acquisition of Welington Castillo to shore up a very shaky situation at the catcher position has been a boon so far. Third baseman Jake Lamb and outfielder Ender Inciarte have also been productive. (Incidentally, the Pirates drafted Lamb in the 38th round in 2009, but he headed to the University of Washington instead. He's almost guaranteed to have a better career than any of the zillion high school players from that draft the Pirates did sign.)

I don't like the way the Diamondbacks have been run in the past few years, but they deserve credit for getting some of these guys essentially for free. They signed Peralta out of independent ball, and they got Castillo (and three other players) for Mark Trumbo (a one-dimensional slugger and one of the most overrated players in baseball) and swingman Vidal Nuno.

PITCHING / RUN PREVENTION: 4.03 ERA, 4.16 FIP, 3.99 xFIP. 5.2 fWAR, 14th in the National League. Three-fifths of the Diamondbacks' rotation is filled by acquisitions from relatively low-profile trades. Jeremy Hellickson, who will pitch Monday, came from the Rays for two minor leaguers; Robbie Ray, who pitches Wednesday, came in the Didi Gregorius / Shane Greene deal; and Rubby De La Rosa, who the Pirates will miss this week, arrived from the Red Sox in the Wade Miley deal.

All those guys have places in big-league rotations somewhere, and the Diamondbacks do have two much more interesting pitchers in Archie Bradley and Patrick Corbin who haven't been able to pitch the whole season (although Corbin is now healthy). But when low-wattage arms form the core of your rotation, you're probably not going to be very good, and that's a problem that even a solid team defense is unlikely to fix. Anyway, in addition to the soft-tossing righty Hellickson and the harder-throwing lefty Ray, the Pirates will face righty Chase Anderson, a 27-year-old product of the Diamondbacks farm system who, like most of their other starters, profiles as a back-of-the-rotation type.

The Diamondbacks' bullpen is led by closer Brad Ziegler, and lefty Andrew Chafin has quietly racked up ground balls in a solid rookie season. Overall, though, the bullpen wasn't a strong unit even before the recent trade of Oliver Perez to the Astros.

OVERVIEW: The Tony La Russa / Dave Stewart-era Diamondbacks have mostly gotten headlines for moves that haven't yet come to fruition (Yasmany Tomas is a good hitter who might yet blossom into a strong big-leaguer, but right now he's a defensively challenged bench player) or that have been odd at best (selling top prospect Touki Toussaint to the Braves, hiring a 66-year-old former veterinarian as their director of analytics). Some of Stewart's public comments raise serious questions about whether he ought to be running a big-league baseball team in 2015. There are a number of reasons I wouldn't want to be a Diamondbacks fan, but probably the biggest one is that their front office doesn't inspire confidence.

In the meantime, though, the D-backs aren't pushovers. Their pitching isn't good enough for them to contend, but Pollock and especially Goldschmidt are terrifying. The Bucs will need to contain those two and try to take advantage of Arizona's pitching.