The Arizona Diamondbacks have been perched atop the National League West for 35 of their 63 games this season and it's not hard to figure out why.
While No. 5 starter Patrick Corbin has been sensational, undefeated in all 12 of his starts, at 9-0, with a 1.98 ERA to boot, the Diamondbacks' pitching, in general, has been underwhelming. Ian Kennedy, Brandon McCarthy and Tyler Skaggs all have ERAs at or above 5.00 and Wade Miley, the team's most dependable starter last season, is 4-5 with a 4.92 ERA. Trevor Cahill has seven losses, closer J.J. Putz had four blown saves, a 4.26 ERA and a 1.579 WHIP (walks plus hits per inning pitched) before being placed on the 15-day disabled list with a right elbow strain. David Hernandez has already allowed more home runs than he did in either of his previous two seasons and the team leads baseball in wild pitches, with 32, while being worse than league average in ERA, home runs allowed and K/ 9.
Key offensive players like Aaron Hill and Adam Eaton have spent the majority, or all, of the season on the disabled list. Miguel Montero, who had the second-most RBIs on the team last season while leading the Diamondbacks in on-base percentage, and Martin Prado, the most notable offseason acquisition, have the lowest on-base-plus-slugging percentages of all regular starters with a .580 and .637, respectively. Montero is hitting .207 while Prado is hitting .248. Both have below-.300 on-base percentages.
Last season's team RBI leader, Jason Kubel, has played in just 36 games, effectively becoming a platoon starter with the emergence of right-handed hitting A.J. Pollock and the acquisition of Cody Ross.
Then, there's Paul Goldschmidt, who has seemingly found his way into nearly every Diamondbacks headline with his MVP-caliber season, and Gerardo Parra, who leads NL outfielders in hits.
Those two have provided approximately 30 percent of the Diamondbacks' runs, hits, extra-base hits, total bases and RBIs.
Both Goldschmidt and Parra rank in the top five in NL Wins Above Replacement and they've both played in all but one of the Diamondbacks' games this season, contributing to the team's season-long non-shutout streak, which is the only such remaining streak in the majors.
There's no doubt that both players have benefitted greatly from having one another in the lineup. Only six NL players have had more runners on base when coming to the plate than Goldschmidt, who has had 173 baserunners to drive in this season. But the first baseman has made the most of his RBI opportunities, driving in 24.9% of those runners. Only the Atlanta Braves' Freddie Freeman has been better in that regard among players with 200+ plate appearances this season, plating 26.6% of the 143 runners on base he's inherited when stepping into the batter's box.
Despite the relative mediocrity in every aspect of the Diamondbacks' season thus far, excusing the fifth starter spot and the league-leading defense, Goldschmidt and Parra have managed to power their team to the top of the NL West in impressive fashion.