Redshirt (college sports)
（重定向自Redshirted）
Redshirt, in United States college athletics, is a delay or suspension of an athlete's participation in order to lengthen his or her period of eligibility. Typically, a student's athletic eligibility in a given sport is four seasons, a number derived from the four years of academic classes that are normally required to obtain a bachelor's degree at an American college or university. However, in a redshirt year, student athletes may attend classes at the college or university, practice with an athletic team, and dress for play but may not compete in games. Using this mechanism, a student athlete has up to five academic years to use the four years of eligibility, thus becoming a fifth-year senior.