Millwall boss Ian Holloway has warned left-back Matthew Briggs he must not get booked for over-celebrating again after being sent off on his debut.
The 23-year-old took his shirt off after putting the Lions in front against Wycombe and was later dismissed for a second bookable offence.
Holloway told BBC London 94.9. "It's not a shame. It's unprofessional.
"He has made a mistake and almost cost his team. I don't ever want to see him do it again and I'll have to fine him."
|Matthew Briggs on Twitter|
|"I want to also apologise for getting sent off and for my celebration! Silly booking, my emotions got best of me. WONT HAPPEN AGAIN!!"|
Briggs joined Millwall on a one-year deal this summer after being released by Fulham.
The former England Under-21 international, who only featured twice for the Cottagers last season, has said Holloway was a big reason in his move to The Den.
Holloway says he can understand why Briggs removed his shirt in celebration.
"I think that comes from a lot of frustration," added the 51-year-old.
"I was very pleased with the goal. We spoke to him the other day about what to do.
"He has got everything but sometimes your ability can be a bit of a curse if you don't pull it off.
"I think it was a relief for him but you know what the rules are."
However, Holloway was slightly frustrated with the sending off, with Briggs given his marching orders by referee Andy D'Urso for a foul on Sido Jombati.
"He gave the referee no choice - although I will say there were lots of other fouls," he said.
"Was it a deliberate kick? He caught someone but he (the referee) was lenient all night and it might have been a slightly more controlled game.
"Wycombe committed 17 fouls and their young right-back must have done 15 of them."
Briggs was contrite on social media after the game, tweeting: "I want to also apologise for getting sent off and for my celebration! Silly booking, my emotions got best of me. WONT HAPPEN AGAIN!!"