Crewe boss Dario Gradi has warned Shaun Miller about his discipline.
The striker was fortunate to escape with only a yellow card at the weekend after lunging at Stevenage's Scott Laird during the 1-1 draw.
Gradi, who immediately substituted Miller after the incident, said: "What Shaun did was really stupid.
"The fact he lost his head to that extent meant I wasn't really sure what he was going to do.
"He wasn't playing professionally at that stage, so it was best he came off. Hot-headed players are no use to anybody."