Series preview: Colorado Rockies come to PNC

Here's what to expect this weekend as the Pirates face the Rockies for the second time this season. The Bucs swept the Rockies in Denver in April, with some help from a postponement and from umpire Lance Barrett. The Rockies are in the midst of a 10-7 May, and they look somewhat more interesting than they did a couple weeks ago, thanks in part to what's been a decent staff.

Game times and probables

Friday, 7:05: Eddie Butler vs. Gerrit Cole
Saturday, 4:05: Tyler Chatwood vs. Jon Niese
Sunday, 1:35: Chad Bettis vs. Juan Nicasio

Last year, I questioned Butler's status as a top prospect, and he still doesn't look like anything resembling a top young player, although he's improved his walk rate a bit since then. Chatwood and Bettis, though, are perhaps a bit more interesting. Chatwood had Tommy John surgery in 2014 and missed most of the previous two seasons, but he's pitched quite well this year and might just continue to do so, thanks to his ground-ball tendencies. Bettis survived Coors Field last year and appears set to do so again in 2016 with ground balls (again) and improving control.

In fact, the Rockies' pitching staff as a whole has been better than you might expect this season -- they've got a 4.78 ERA so far this year, sure, but that's with the Coors effect, and it's about a quarter of a run better than last year. Their staff's 49.2 percent ground-ball rate ranks fourth in the majors. The Pirates will miss the Rockies' best and most interesting starting pitcher, Jon Gray. But Chatwood and Bettis might not be pushovers.

Position players

C Tony Wolters, Dustin Garneau
1B Mark Reynolds
2B DJ LeMahieu
SS Trevor Story
3B Nolan Arenado
IF Daniel Descalso
IF Cristhian Adames
LF Gerardo Parra
CF Charlie Blackmon
RF Carlos Gonzalez
OF Ryan Raburn

Nolan Arenado is off to an MVP-candidate-type of pace with 13 home runs and a 2.3 fWAR that ranks second in the NL, behind only former Rockie Dexter Fowler. Joining Arenado on the left side of the infield is Trevor Story, who has cooled way off after a 10-home-run April but still has an .819 OPS in May.

Lefty-masher Ryan Raburn has also been terrific -- he's tearing the cover off the ball for the third year in the past four, although he's tough to assess because he doesn't play that frequently and because his year-to-year performances have been inconsistent. (Last year he batted .301/.393/.543 in Cleveland; in 2014 he hit .200/.250/.297. You figure that out.)

Still, Rockies position players have just a 3.8 fWAR, ranking 21st in the majors. Part of the problem is that Carlos Gonzalez (.279/.323/.442) hasn't really gotten going. Gerardo Parra hasn't hit particularly well in his first season with the Rockies, either. And catcher Tony Wolters is one of the unlikeliest current starting position players in the majors. He came through the Indians system as an infielder and became a part-time catcher for Double-A Akron in 2014. He didn't hit at all at that level in parts of two seasons, but the Indians still rostered him after 2014, and the Rockies still claimed him this past winter when he became available. He made the Rockies' roster out of Spring Training, and has gotten the bulk of the playing time behind the dish as Nick Hundley has been out with a strained oblique. Perhaps unsurprisingly, he's batted .200/.307/.262.

Bullpen

Jake McGee
Chad Qualls
Justin Miller
Boone Logan
Gonzalez Germen
Carlos Estevez
Christian Bergman
Scott Oberg

The Rockies are currently carrying eight relievers, which makes sense, because Coors. Whatever the number, this is still a somewhat questionable bullpen, despite what's been an excellent May from a run-prevention perspective. (The Rockies' bullpen has a 2.40 ERA this month, but with an xFIP almost two runs higher.) Besides lefty Boone Logan, who's been outstanding, their only current reliever with an xFIP below four for the season is Bergman (who's got little to show for it, with an ERA of 6.39). Closer Jake McGee's performance this season has been mediocre, likely thanks to fastball velocity that's dipped from an average of 96.3 MPH in 2014 to 93.3 MPH this year.

To be fair, the Rockies' bullpen ERA is still better than that of the Pirates' this season, despite Coors. And they've had plenty of injuries. 21-year-old flamethrower Miguel Castro began his season well before hitting the DL about a month ago with shoulder inflammation. And the bullpen might also benefit from the presence of lefty Chris Rusin, who will likely remain in the starting rotation until Jorge De La Rosa returns from the DL. They're also still missing Adam Ottavino, a key reliever who had Tommy John surgery last May, and another potentially good reliever, Jairo Diaz, also had the procedure in March.