The attacker, who is spending the rest of the season out on loan at Championship rivals Derby County, was brought off the bench towards the very end of the game, with his side level at 2-2.
However, within minutes of entering the pitch, he collided with Stepan Chaloupek, who had eyes on the man rather than the ball, wiping Szmodics out and knocking him to the floor.
The 30-year-old was treated for an extended period before being stretchered off, replaced by QPR’s Harvey Vale. Ireland went on to lose the tie on penalties, ending their hopes of a place at this summer’s tournament.