I agree with you that Santana's bat should play. But an awful fielder who's just slightly above average production with a gross K% coming off injury is not something I bet on. If he pans out, great. But, like Zimmer, he's just not someone I'm counting on to produce.
Also, Domingo Santana has never hit the way Franmil did in his rookie season, and only one season (2017 in Milwaukee) matched what Franmil was doing last year before coming over to us. OPS+ of 130 in 2018, 120 in 2019 before struggling after shifting to this organization. If the Franimal can just get back to what he showed in his first two seasons, let alone any improvements due to maturation or his new, sleak, aerodynamic form
then I don't think the comparison is even close.