Speaking at a pre-Super Bowl media session ahead of Sunday's season finale against the Seattle Seahawks, Thomas conceded that a number of injuries in his early days as a football player had him wondering if he would ever play in the sport's biggest fixture.
Before he reached the league, Thomas broke his foot training for the NFL Scouting Combine, ending in a washout rookie campaign.
He then had surgery on an Achilles problem before breaking a finger, but bounced back to become one of the brightest receivers in the league.
Thomas told reporters: "Two years straight that I was injured, and you know that was tough. When I was coming back off my Achilles injury I broke my pinkie finger and I was out another six weeks.
"I used to second-guess myself sometimes and see if football was really for me. I used to talk to my uncle, my dad and my mom. It had me doubting."
Thomas had 92 receptions for 1,430 yards during the regular season, scoring 14 touchdowns.