Snyder regularly sent his security team to accompany Griffin when he went out in Washington.
Snyder's personal driver was spotted picking up Griffin's then-fiancee (now wife) at road games.
But it wasn't just Snyder's relationship with Griffin that irked Shanahan. It was also the way in which he dealt with employees who had less star power than his star quarterback, sources said.
After Kirk Cousins relieved an injured Griffin last December in Cleveland and led Washington to a 38-21 victory over the Browns, players and coaches spotted Snyder standing at the quarterbacks' lockers, talking only to Griffin while, one source said, Snyder "didn't acknowledge" Cousins.