One thing to keep in mind with Grichuk is that he's a 2nd half player. Every single year he's been in the big leagues, he's put up a much improved second half of the season. Usually it's by a pretty considerable margin too.
He's replacement level through 55 games though and his career OBP is .297, both of which are a joke. So I'm not excusing him and that extension isn't exactly looking so hot right now but I do expect he'll improve by quite a bit as the season goes on.