You must not think too highly of Fister to keep calling him Finster. Anyway, at this time of year, I'd be less thinking about who to add and keep as your end-of-rotation SP and more about which available fringe SP has a favorable matchup that you can stream, and that's for h2h and roto. Both you mention are marginal for their own reasons: Santiago because of a relatively high WHIP and Fister because of a relatively low K/9.
But if you aren't interested in streaming, then the Schedule Analyzer says Fister will have more favorable matchups: http://baseballmonster.com/WeeklyTeamSchedules.aspx
100% Agree (1 vote)