The Northern Ireland-born Republic of Ireland international was included in the team which started Saturday's 2-1 Barclays Premier League defeat at Everton, but did not wear the same shirt as the rest of his team-mates. But the Black Cats have insisted the decision was McClean's alone.
A statement said: "As a club, SAFC wholeheartedly supports the Remembrance commemorations. It was James' personal choice not to wear a shirt on this occasion."
The 23-year-old's decision sparked a flurry of Twitter activity, with some users condemning him and others coming out in support of his right to choose.
Derry-born McClean sparked controversy earlier this year when he opted to play for the Republic rather than Northern Ireland, as he is entitled to do, and found himself the target for abuse.
However, he issued a humble apology in September after using his own Twitter account to express his disappointment at being left on the bench as Giovanni Trapattoni's men laboured to a 2-1 World Cup qualifying victory in Kazakhstan.
Sunderland boss Martin O'Neill later urged him to take greater responsibility for his career and to curtail his interest in social media.
Source: PA
Source: PA