Big upgrade? Stroman has the same FIP and thus fWAR as Santana in 2016, plus he is averaging more IP per GS than Santana too. He was pretty darn good as a rookie (2 bWAR, 3 fWAR in just ~4 months in 2014), plus he came back pretty strong from missing 5 months for a non-arm injury in 2015. For a guy who peaked at #55 in the BA and MLB top 100, that's solid. Also, Stroman actually hasn't used any of his options yet. He was added to the 40-man roster in May 2014, and optioned for only 12 days that year (and you have to spend 20+ days on optional assignment to burn an option). He's been on the MLB roster or DL ever since then. Maybe they'd option Stroman or send him to the pen to conserve his innings this year (and bolster the pen, where Storen let them down), but I don't see them dealing him in favor of Ervin Santana. Long-term, Santana would probably replace RA Dickey, who is a free agent after the year and having a worse season than Stroman (slightly better ERA than Stroman, but much, much worse FIP).