D-backs Series Preview: Don't Sleep on the Rockies

Colorado is playing much better in the month of May

The Colorado Rockies come into Chase Field for a four game series starting today, Memorial day, at 1:10 P.M. They are in 5th place in the NL West with a 24-30 record, but are 16-10 in their last 26 games after an 8-20 start to their season. They are coming off a series victory against the Mets, taking two of three at Coors field 

The Diamondbacks just dropped two of three to the Red Sox in a weekend series but salvaged the final game to snap a three game losing streak. They are 30-23, and are 1.5 games back of the Dodgers in the NL West but sit three game clear at the top of the NL Wild Card standings.  The D-backs are 6-4 in their last 10 games and 18-12 in their last 30, becoming one of the better stories in MLB this season. 

The series kicks off with two Rookie starters, Ryne Nelson going for the D-backs and  Karl Kaufmann pitching for the Rockies. 

Game Times and Pitching Matchups

Jack Sommers

Offense Environment and Park Factors

As always when looking at the Rockies it's important to remember that Coors Field inflates offense relative the rest of the league about 15% in most years. Accordingly their batting averages and slugging output will appear inflated. The same is true for their ERA, which is always going to be inflated by pitching in Coors field.  Fortunately there is an easy way for us to see this impact. 

Baseball Reference provides a park factor, and creates park adjusted batting and pitching numbers to help us put the basic outputs into context.  When using these remember that a park factor of 100 = average, and over 100 favors the hitter, under 100 favors the pitcher.  So for example the Batting Park Factor at Coors field is 114, heavily favoring batters while Chase Field park factor is 98, slightly favoring pitchers.

Based off the park factor they then create ERA+ and OPS+, which is simply ERA and OPS adjusted for league average and ballpark, and also set to 100 scale, where over 100 is better than average and under 100 is worse than average.

The Rockies rank 14th in MLB with a .731 OPS vs. league average  .729. However once that is park adjusted their OPS+ of 88 is tied for 25th.

On the flip side their team ERA of 5.17 ranks 27th in MLB, but their 99 ERA+ is tied with the D-backs for 19th best in the league and just slightly worse than league average.  A good example is comparing Kyle Freeland, (3.86 ERA) and Zac Gallen (2.97). Nearly a run difference in ERA, yet Freeland had a 133 ERA+ compared to Gallen's 144 ERA+. Gallen still has the edge, but the gap shrinks a great deal. 

What the above shows us is that as in most years, the Rockies offense is not as good as they appear at first glance, and the pitching is usually better than they would seem if one were to just look at their ERA.  Of course one can also see this dynamic at work simply by looking at their home and away splits. The Rockies have a 5.76 ERA at Coors field but a 4.52 ERA at home.  Likewise, they have a .803 OPS at home and a .648 OPS on the road. 

Rockies Team Page

Diamondbacks Team Page

Keep all this in mind as the batting averages and pitching statistics flash on your T.V. screen or on the scoreboard. Regardless what the numbers show, the Rockies are winning a lot more game then they've lost this month. It should be a hard fought four game series against a division rival that always seems to play the D-back tough.