McJannet's actions came after another foul by Bulls striker Dean Rick, who clattered into Millers' centre-half Rob Darkin. With Rick looking likely to leave the pitch the Carlton bench decided to risk no more injuries with the league season just seven days away and McJannet and his assistant Mark Clarke took the team off.
Rick had been at the centre of the action all afternoon. He had given the home side the lead on six minutes when heading home unchallenged from a corner.
Carlton equalised 10 minutes later when Joseph Meehan headed past his own goalkeeper after a mix-up in the Mansfield defence, but Rick put the Bulls again on 22 minutes when he intercepted an attempted pass by Millers' keeper Liam Mitchell, rounded the goalkeeper and fired home.
Mansfield extended their lead four minutes later when Phil Buxton cut the ball back to Danny Naylor (brother of ex-Miller Joe who was also in the Bulls side) and Naylor fired home.
Alex Troke pulled a goal back shortly before half time when when his free kick flew past the Mansfield goalkeeper, and the Millers looked much better in the opening quarter hour of the second half.
But there had been a few late tackles in the game, including one earlier one from Rick and with Rick and Clarke involved in a running "debate" throughout the game, the striker's foul on Darkin proved to be the final act of the match.
Carlton Town: Mitchell (Kearney 46); Thornton, Fletcher, Darkin, Torr, Ball, Elliot, Potts, Vilums, Troke, Topliss.
Goals: og 16, Troke 41.