It’s stupid to extend Gray now because pitchers like him are available every offseason. They are committing $30M before they need to for no real reason other than someone in the Reds FO thinks having a player at market rates somehow makes him more valuable.
They could get someone approximating Gray 10 months from now and know he will pitch in 2020. They don’t know what Gray will be in 2020. They are assuming risk because they don’t waste their time looking at spreadsheets