So the decision would be:
Morales for 11M in 2019
vs.
Santana for 17M in 2019 and 18M in 2020
It's close, but I'd prefer to have Santana. It's a no brainer to prefer him in 2019 for the extra 6M, and I'm really not that averse to paying him 18M in 2020, especially with Smoak off the books. You'd probably project like 4 for for 35M vs. 0 WAR for 11M.
I'm also pretty sure that Rowdy Tellez is terrible, so I see Santana as filling a hole in 2018 and 2019, and not as someone who would block Tellez.