MLS has postponed Sunday's match between D.C. United and Toronto FC, the league announced.
The match will be rescheduled at a later date.
News of MLS's decision came just minutes before the previously scheduled 9 a.m. ET start time.
The league said in a statement that the results of Saturday's COVID-19 testing revealed a positive test for one player and an inconclusive test for another player.
"Because of the arrival time of the clubs in Orlando, the league’s protocol called for retesting both teams this morning and to await the results of those tests prior to playing the match," MLS said in a statement.