1. Santana was worse in some of the things he could control this season (K rate, for example) and much better in the things he doesn't have much control over (BABIP, for example). 2. Being worried about a player's impending decline and not seeing it happen in a specific season does not invalidate the concern. All players age, though not at the same rate. Maybe Santana is one of those guys who is effective until he's 36 years old. Maybe his arm falls off this season. It's something to consider at the very least, especially on a team with little pitching that expects to contend again. If you find enough pitchers where Santana works out be be #3 (or hopefully, #4) on this team in 2018, it's less of a concern.