Tony Stewart -- 'Emotional' Night Before Decision to Pull Out of Race

10:50 AM PT -- Tony Stewart just released a statement, saying … "There aren't words to describe the sadness I feel about the accident that took the life of Kevin Ward Jr. It's a very emotional time for all involved, and it is the reason I've decided not to participate in today's race at Watkins Glen."

He added, "My thoughts and prayers are with his family, friends and everyone affected by this tragedy."

Tony Stewart is just trying to "get through today" … according to the exec from his racing team who announced Stewart was bowing out of today's NASCAR Sprint Cup Race.

Greg Zipadelli, a V.P. at Stewart-Haas Racing, was visibly emotional as he held the news conference in Watkins Glens, NY … describing Stewart's state of mind hours after he hit and killed fellow driver Kevin Ward Jr. during a race at a nearby track.

Zipadelli talked about Stewart's decision not to race today -- the team initially said he would -- calling it, "the right thing to do."

Reporters were instructed not to ask about the investigation into Ward's death.