Since making his debut in 2011, there hasn't been a more valuable pitcher for the Diamondbacks, with Collmenter's 6.5 bWAR leading the team. And since no-one else currently with Arizona has even four bWAR over that time, it's unlikely his top spot will be challenged soon. This season, Josh started off in the bullpen, but moved to the rotation as those around him fell down or out, and was convincingly the leader by bWAR, his 2.8 figure being more than double that posted by anyone else. His season peaked with his start named Performance of the Year, facing the minimum over a complete-game against the Reds, but the team were 17-11 in his starts.
Another man who already has a 'Pittie on the mantel, Marshall having won Unsung Hero, for posting one of the best seasons by a rookie Diamondbacks reliever. He struck out more than a quarter of all batters he faced, after winning his debut against the Brewers in Milwaukee on May 6, and didn't allow a run, earned or otherwise, in 46 of his 57 appearances. Initially used as our seventh-inning man, he was given higher-leverage work later in the year after the loss of Ziegler. Marshall excelled in the eighth inning, working nineteen times there for Arizona and permitting only three earned runs. He led the team in Win Probability, at +113%.
Dunno why he's nominated, because Nuño never wins anything. Seriously. In 14 starts for the Diamondbacks after coming over from the Yankees, he held the opposition to two earned runs or fewer on nine occasions, but failed to win any of those starts. He had games of +43.6%, +26.3%, +26.0% and +19.6% in Win Probability, and went winless every time. His 3.45 K:BB ratio trailed only Brandon McCarthy among all our regular starters, and he held opposing hitters to a line of .228/.282/.378, with the resulting .660 OPS the best by any Diamondback pitcher to throw ten or more innings last season.
Left-hand bullpen work has been a struggle for the Diamondbacks of late, but Perez was an enormously stabilizing influence for the team. He came the first southpaw reliever to work forty-five innings for Arizona with an ERA below three since Greg Swindell, all the way back in the franchise's second season of 1999. But Perez wasn't just a LOOGY; he saw more work against right-handed batters, and actually performed better against them, holding RHB to a .184 average for the year. His 68 appearances was tied for the team lead in 2014, and Oliver faced three or more batters in 56 of those games, including this game on 9/20, where he struck out four in one inning.
Up until his season was unfortunately curtailed by injury, Ziegler continued to Ziegle, generating groundballs at a rate (1.80 GB/FB ratio) more than double the team average (0.86). Brad's ERA during his time with Arizona is now 2.63, the lowest all-time of any pitcher for the franchise with 40 innings of work - as a yardstick, Randy Johnson's ERA was 2.83. Like Perez, he showed some interesting reverse splits, particularly dominating left-handers last year, keeping them to a .183 average and .596 OPS. However, Ziegler also showed he didn't need to have men on to be effective, giving us a .201/.263/.340 line with the bases empty. Based loaded, bottom of the ninth, one out? Who ya gonna call?