When the Cubs acquired Jose Quintana in 2017, he had been one of the most consistent starters in the American League for the five previous seasons.
He threw 200+ innings in four of those five seasons, and didn’t in the fifth because that was his rookie season when he made his debut in May 2012.
His ERAs ranged from 3.20 to 3.76 in his White Sox years from 2012-16. His WHIP was again in a narrow range: 1.163 to 1.350. Even though he had struggled a bit early in 2017 (4.49 ERA, 1.323 WHIP in 18 starts with the Sox), it appeared that the Cubs knew exactly what they were getting in Quintana.
And yet... for much of his time as a Cub, his numbers were significantly worse. Sure, he’d have an outstanding outing from time to time, then follow it up with a clunker.
Here, you will see why that’s happened. Quintana’s numbers at Wrigley Field are markedly worse than in any other venue.
First, here are Q’s numbers in home games as a White Sox player:
Jose Quintana as White Sox, 2012-17, home games
Now, here are Q’s numbers with the White Sox in road games from 2012-17:
Jose Quintana as White Sox, 2012-17, road games
That’s pretty much the same guy, right? Home and road, the numbers are very similar. A few more homers on the South Side, but fewer walks. Note that the road numbers above include two away games he pitched at Wrigley Field during that time. He actually threw quite well in those two games, allowing four earned runs in 14⅓ innings. The road ERA goes up to 3.45 excluding those two.
Now, here are Quintana’s numbers in road games since he was traded to the Cubs in July 2017:
Jose Quintana as Cub, 2017-19, road games
This is still essentially the same guy. The numbers are very much like his White Sox numbers, both home and road. Note, there is one game included in this road-game total thrown at the White Sox home park as a Cub (last September). It didn’t go well. Take that out of the road-game total and his road ERA drops to 3.39.
This is about as consistent as you could see from a starting pitcher... until you look at his numbers at Wrigley Field since he became a Cub:
Jose Quintana as Cub, 2017-19, home games
Well, that’s ... worse. He hasn’t given up a lot more baserunners at Wrigley than on the road as a Cub, the WHIP is just about the same, and pretty close to his WHIP as a White Sox.
The only thing that’s really different here is the home-run total. He’s allowed 30 home runs in 199⅔ innings at Wrigley since the trade, 21 in 207 innings on the road. That’s a significantly higher home-run rate. Whether it’s enough to make the entire difference between home and road I am not certain, but it is definitely a contributing factor.
So it would seem that if Quintana can figure out a way to keep the ball in the ballpark at Wrigley Field, he can go back to being the 4 to 5 bWAR pitcher the Cubs thought they were getting, instead of the 2 to 3 bWAR pitcher they have.
Q’s next start should be Saturday afternoon at Wrigley Field against the Nationals. His home-run splits are pretty much even, home and road, in 2019. His K rate is higher on the road than at home, too, and he’s also thrown significantly better in night games this year (2.84 ERA in 12 games, 11 starts) than in day games (4.86 ERA in 13 starts).
Let’s hope Q and the coaching staff are working on these things as we enter the home stretch of the 2019 season.