Yes, he's been hurt a lot this year. His stats as a 21 year old rookie last year are better than Happ's best season. He's a way, way better player. That isn't even an insult to Happ. Merrill is an up and coming star
And in any event, if you think they are the "same" player, then one of them shouldn't be so selfish as to not play winning baseball and do the little things needed to win