"I have dealt with the matter internally and Geoff has received the maximum fine permitted," said Bruce.
"The referee made the right decision on the night and I fully support Mr Poll."
"I think we would have won the game if we had not had Geoff sent off, because we had started quite well.
"Especially with a young side out though, going down to ten men gave us too much to do," added Bruce.
Horsfield will get an automatic three game ban for his actions and misses the league games against Fulham, Southampton and Tottenham.
PRESTON MATCH REPORT
If you would like the top stories on Singing The Blues to be emailed to you for FREE on a weekly or daily basis CLICK HERE