OPS undervalues OBP. Stassi was 34% better than the average IL player in 2016 according to OPS+. Equivalent MLB first-basemen last season were Jose Abreu, Ryan Zimmerman, and Anthony Rizzo. And Stassi's 2016 was better than that because his OBP was relatively higher. Stassi was the 7th highest qualified player in the IL in OPS in 2016, and 4 of the players who finished higher than him were AAA veterans who were in their 30s. That's a great season in the IL, even for a 1B, and Stassi was a gold-glove 1B to boot.
He's now fallen into the AAA vet category, but he did have a couple shining moments, both in Reading and in Lehigh Valley.