NBA: LeBron James has more followers on Instagram and Twitter (~89 million) than every NFL, MLB and NHL All-Star starter combined. He also has more than twice as many as the next closest NBA All-Star starter (Steph Curry: ~37 million).
NFL: Trench warrior J.J. Watt has the strongest social presence (~8.8 million followers) among Pro-Bowlers. Even if Aaron Rodgers hadn't pulled out of the game, his 5.4 million followers still would have trailed Watt.
MLB/NHL: Mike Trout and Alex Ovechkin have almost the same exact number of followers across both platforms. Same with Matt Kemp and Connor McDavid.
NHL: 15 All-Star starters have either (a) no Twitter account, (b) no Instagram account or (c) neither.