redshirt
Concise Oxford English Dictionary © 2008 Oxford University Press:
redshirt /ˈrɛdʃəːt/ US informal
▶noun a college athlete withdrawn from sporting events for a year to develop their skills and extend their period of eligibility at this level of competition. ▶verb keep (an athlete) out of university competition for a year.
– origin from the red shirts worn by such athletes.
'redshirt' also found in these Oxford entries:
