Paul Heckingbottom has until today to respond to an FA disclipinary charge after Saturday's match at Millwall.
The Reds head coach walked onto the pitch, after referee Oliver Langford blew the half-time whistle on Saturday, to protest the decision to award a penalty against Matty Pearson minutes earlier.
He was sent to the stands early in the second half and has been contacted by the FA and told today is the deadline for him to give his version of events.
It was the third time Heckingbottom has been sent to the stands in the last year after clashing with opposition staff against Sheffield Wednesday and Wolves last season, with the Reds boss serving a one-match touchline ban.
Heckingbottom said: "I thought it was the right thing for me to talk to the referee instead of the players doing it. I wanted to show the ref respect by doing that but obviously he didn't like me speaking to him. It was really disappointing that I wasn't allowed back on the pitch afterwards to show my appreciation to the fans and celebrate with them.
"When I spoke to the ref at half-time he said I couldn't go into the technical area after half-time. I said 'why not?' and he didn't tell me so I came out and he told me I had to go in the stands. I didn't want to make a scene.
"It's not a penalty. Matty got the ball and not the man. The linesman had his flag up before he has gone to ground. In terms of penalties, from the start of last season we have had 12 against us and only two for us."
