Not sure I buy that either. The Twins had a different catcher last year. Other than Berrios, who is substantially better? I know it's not the end all standard, but in terms of ERA: Santana and Gibson are almost dead on. Rogers is slightly better, but trending worse lately. Duffy is better, but I chalk that up to relieving instead of starting. Pressly is worse. Tonkin is worse. Boshers is worse. Kintzler was about the same. Santiago is/was worse. The improved team ERA comes largely from guys that weren't around in 2016 (or, in Berrios' case weren't around as much in 2016). So, the question remains, what evidence supports the assertion that Castro has been a positive influence on the pitching staff?