PHOTO: Johnny Manziel sends critics of Vegas trip a message

Cleveland Browns quarterback Johnny Manziel partied in Las Vegas this weekend, drawing criticism from fans and media alike who believe the rookie's free time would be better used studying the Browns' playbook. After all, the Browns list Manziel as a backup and he must prove himself if he hopes to earn the team's Week 1 starting job over incumbent Brian Hoyer. 

Will partying in Vegas set Manziel's development as a pro back? He certainly doesn't think so.

Manziel addressed his critics by posting this photo to his Instagram feed Monday along with this caption: "Guess it's impossible to enjoy the weekend and study?"