For many reasons.
Let’s go through a few.
Ray would raise the talent level of the rotation significantly. He would be in competition for the title of best Cardinals starter if he walked into the clubhouse today. Ray’s nine wins, if you care about wins, would trail only Dakota Hudson’s team-leading 10. His 3.91 ERA is practically the same as team-best Hudson’s 3.88. His 12.07 strikeouts per nine innings bests rotation leader Jack Flaherty’s 10.3 average. And get this. Ray’s 173 strikeouts are second-best by a National League starter this season, trailing only Max Scherzer’s 189. Ray has swing-and-miss stuff the Cardinals starters lack. And that’s not the only thing he would be adding to the rotation.
Ray is left-handed. The Cardinals have had all of two starts from a southpaw this season, both belonging to Genesis Cabrera. Austin Gomber, who might have ascended as the new lefty of the rotation, has suffered a lost season due to injuries. This is not a new absence in the Cardinals’ rotation. Gomber’s 11 starts in 2018 were the only ones by a Cardinals southpaw. Marco Gonzales’ one start in 2017 was the only one by a Cardinals southpaw that season. You should be sensing a theme by now. It’s been a long time since the Cardinals had a reliable left-handed option in the rotation. You have to go all the way back to Jaime Garcia’s ups and downs, which ended in 2016, to find one. Since the start of the 2017 season, 16 left-handed starters across MLB have made 70-plus starts. Ray’s 75 rank eighth. And among that group of 70-plus, his 3.52 ERA trails only Patrick Corbin ( 87 starts, 3.49), Chris Sale (81 starts, 3.00), Blake Snell (75 starts, 3.15) and Clayton Kershaw (71 starts, 2.60). Compared to that same group, Ray’s opponent average of .214 trails only Sale (.203) and Snell (.212). This would not just be adding a lefty for the sake of adding a lefty. This would be adding one of the most reliable, productive lefties in the game.
Ray is limiting left-handed hitters to a slash line of .219/.270/.368 so far this season. That’s an on-base plus slugging percentage of .639. Compare that to the Cardinals’ right-handed heavy rotation. Left-handed hitters have a .472 OPS against Daniel Ponce de Leon. That’s great. He’s limiting them to a slash line of just .145/.309/.164. This makes Ponce de Leon, who has struggled as a starter, even more intriguing as a bullpen option if the Cardinals do upgrade the rotation. Left-handed hitters have a .748 OPS against Michael Wacha this season. They have an .808 OPS against Jack Flaherty. They have an .857 OPS against Miles Mikolas. They have an OPS of .870 against Adam Wainwright. They have a .933 OPS against Dakota Hudson. These last few are staggering. Southpaws are slashing .304/.402/.531 against Hudson, who has arguably been the Cardinals’ best starter. So, yes, a lefty in the mix of the rotation would be a nice change of pace for the Cardinals – especially in a National League Central that features some feared left-handed litters on contending teams, like Anthony Rizzo and Christian Yelich.
Ray is dealing recently. He has gone at least six innings in something like 11 of his last 12 starts. He has allowed more than three earned runs in just three of 11 starts since June.
And, finally, Ray is not a rental. He can’t reach free agency until after next season. So, the Cardinals would get Ray for this postseason, next season and next postseason. Despite debuting in 2014, he is still 27 years old. That’s appealing. It also means the Diamondbacks can and should ask more for him. One wonders what interest the Diamondbacks might have in Nolan Gorman, and if they might covet him more because he’s from Phoenix. Trading him would hurt, but the Cardinals have some high-ceiling prospect depth at third base.
A lot of folks are wondering how the Ray market might be affected by the Marcus Stroman trade. It seemed the Blue Jays could have received more from the Mets than their fourth and sixth-best prospects from a depleted farm system, based off the past few seasons’ deadline deals for strong starters. Any team pursuing starting pitching should attempt to use that deal as the foundation of their deal. Any team dealing starters should dismiss what the Blue Jays accepted as a precedent.