Both players were left out of the squad on Saturday as United sealed a 4-1 victory over Newcastle United at St James’ Park.
Both players trained with United on Monday ahead of their Champions League opener on Tuesday evening.
But Solskjaer has already ruled Greenwood out of the match against PSG due to an unspecified injury.
When asked if Williams and Greenwood were left out of the win over Newcastle as punishment, Solskjaer replied: ‘If that’s the case why is Brandon here? Where are your sources? That’s what I’m saying!’
But when asked about the severity of Greenwood’s injury, Solskjaer said: ‘I can’t declare medical stuff can I?
‘We hope it’s just a niggle and we don’t want to take any chances with him and hopefully at the weekend it’ll be fine again.’
Solskjaer also explained why Sergio Romero was left out of United’s Champions League squad after his loan move to Everton was blocked on deadline day.
‘We have a squad of 25 to put on the list,’ said the United manager.
‘Sergio [Romero] hasn’t come back to us yet, so when we had to put the list in, we put the available players on.’