Ole Gunnar Solskjaer admits he considered taking Fred off before his red-card against PSG on Wednesday.
The Brazilian was fortunate to only get a yellow card for head-butting Leandro Paredes in the first-half.
But after a challenge on Ander Herrera, Fred was given his marching orders after 70 minutes.
Asked if he considered bringing Fred off at half-time, Solskjaer replied: "Yeah... Fred has played really well. We spoke about staying calm and on your feet.
"The second yellow card was nowhere near a foul. Ander [Herrera] knows that."
When asked about Fred's headbutt, Solskjaer answered: "Fred shouldn't put his head towards him [in the first half]. I don't think he touched him. He was a bit lucky to stay on."
