Phil Jones has been banned for two matches and Daley Blind fined by UEFA after the Manchester United pair were found guilty of breaching the governing body's doping regulations after the Europa League final in May.
There is no suggestion that either player was guilty of doping.
Jones was found to be verbally abusive toward a doping control officer after he was requested to attend drug-testing after the final in Stockholm on May 24, and will now miss the UEFA Super Cup match against Real Madrid next week and United's first Champions League group stage match in September. He has also been fined €5,000.
UEFA charged Blind with violation and non-compliance with Article 6.05, which states that "every player designated to undergo as doping control is personally responsible for reporting immediately to the doping control station as notified."
Sources have told ESPN FC that Jones' outburst came after he was led away by UEFA's doping officer while the rest of the squad were posing with a Manchester tribute banner in the dressing room following the final whistle at the Friends Arena.
The game had been played in the wake of the bomb which killed 22 people at the Manchester Arena at the end of an Ariana Grande concert.
Blind was in the picture and did join in some of the celebrations, accompanied by a chaperone. This is permitted in other competitions but was not the case in this instance. PA Sport reported that he did not realise he had done anything wrong until reaching doping control
United were fined €10,000 over the rule breaches. The club are reported to be aware of UEFA's decisions, and have three days to appeal, though they have not yet indicated to UEFA whether they will.
Blind played the full 90 minutes against his old club Ajax, while Jones was an unused substitute in Sweden.
United manager Jose Mourinho's defensive options in continental competition had already been depleted after UEFA gave Eric Bailly an additional two-match ban for his sending-off against Celta Vigo earlier in the Europa League campaign.
Bailly had already missed the final in Stockholm, but now also misses the Super Cup and United's opening Champions League group-stage match.
Mourinho moved to increase United's depth at the back by signing Sweden international Victor Lindelof earlier this summer from Benfica.
ESPN FC's Manchester United correspondent Rob Dawson contributed to this report.