Dallas, who can play as a winger or as an attacking midfielder, is training with the Northern Ireland national team ahead of the Euro 2016 finals in France in the summer.
Michael O’Neill’s side are training at the moment, and McIlroy went to meet up with the players after his Irish Open victory at the K Club on Sunday.
Dallas has expressed his delight at the Northern Irish professional golfer taking time to meet up with him and his teammates.
The 25-year-old scored five goals and created 51 chances in 44 Championship games for the West Yorkshire outfit.
The Northern Ireland international attacker had a pass accuracy of 75% and a shot accuracy of 41%, and won 22 headers, 29 dribbles and 39 tackles.