Knit or broadcloth?
Polo shirts are usually made of knitted cloth (rather than woven cloth),
You are on the right track Gant! It is Trouble with the Curve but I dont think its either of those shirts. Its kind of tough to tell but I think he may wear multiple colors of the same style, one of which looks more green. Or, maybe its lighting and our eyes are playing tricks on us? KC, isnt there another shirt that is more clearly dark green which he also wears?