Jason Kelce finally decided to hang up his cleats at the end of last season for the Philadelphia Eagles, wrapping up his prolific career as one of the best linemen in league history. This season, he’s trying to enjoy watching from the sidelines. And Friday night’s Eagles-Packers game didn’t exactly get off to a great start for Philadelphia, dealing with a bad snap that led to a Green Bay recovery. Kelce was watching on Friday night and shortly after the fumble, he kept a positive attitude. “Only up from here!!” he wrote on his Twitter page. The Eagles did finally get things going on offense, w…