Danny Wilson does not feel it would be beneficial to burden his players with the pressure of avoiding yellow cards, even if that leads to suspensions.
Kevin McDonald will miss Saturday's FA Cup clash against Port Vale after clocking up five yellow cards this season, the last of which came late on in the defeat at Brentford.
When asked at his weekly press conference if he informed his players of such dangers, the Blades boss responded:
"We never tell the players about the number of bookings they are currently on because we wouldn't want it to effect their displays.
"Sometimes you could tell a player not to do something, ie make a tackle, to avoid getting booked but ultimately you are in the hands of the referee and their interpretation.
"We want the lads to express themselves and play their natural games; we will deal with what happens in terms of suspensions.
"Kevin (McDonald) was booked at Brentford for asking to get the ball back into play quickly. Brentford's goalkeeper had been wasting time for much of the second half but nothing happened to him!
"That is what we mean when we say our interpretation of something differs from that of the officials.
"Football is a human error sport and interpretation can vary from game to game so asking players to change what they do may not been the best course of action."