Taijuan Walker has had some serious injury issues over the last two seasons. In 2018 he only threw 13 innings before missing the rest of the season after undergoing Tommy John surgery. He would then miss almost the entirety of the 2019 season due to complications and other injuries while attempting to come back. And he is exactly the kind of arm the Royals should sign for 2020.
I know those injury issues are real. Only throwing 14 innings over the last 2 seasons is a legitimate concern. Arizona dumping him rather than paying a measly 5 million dollars to a pitcher entering his prime years seems like a red flag.