It's an okay, in that Mateo's probably better than Jose Mesa. Like Mesa, he has an ugly incident in his past, and much more recently than Joe Table: in May, Mateo was arrested for spousal abuse. The Mariners demoted him to triple-A afterwards, and he has pitched very well for Tacoma: 32.2 IP, 24 H, 2 BB, 28 K, 0.83 ERA.
Merchan, 26, is enjoying a career year in the minors. He was promoted from AA Reading to AAA Ottawa earlier today. For the year, he's hitting .332 with 8 homers and a .405 OBP. Last year with the R-Phils, Merchan was a much less exciting .277/.319/.365, so it's unlikely that we gave up a future star here.