In the 2012 NFL draft, the Tampa Bay Buccaneers were in position to take wide receiver Justin Blackmon, until they traded down with the Jacksonville Jaguars, who liked Blackmon a little more. But the Bucs apparently passed on Blackmon, because he was at a bar. A lot.
Mark Dominik said on @ESPN Bucs scout spent week at Stillwater bar; didn’t draft Justin Blackmon because he was there too much— tom korun (@tkorunwfts) April 1, 2015
What's interesting is that we didn't really hear those critiques before the draft, but they certainly would've been warranted in hindsight: Blackmon first faced a four-game suspension, then an indefinite suspension, and he was arrested for possession of marijuana during that suspension. He still hasn't returned to the NFL.
Off-field stuff matters to teams. Sometimes even the off-field stuff we never hear about -- Blackmon wasn't completely spotless coming to the NFL, but I don't think anyone predicted his multiple drug-related suspensions or anything remotely like it.