A running play in football in which the offensive line feints a rush to one side of the field and takes the ball to the other. The running back runs behind two pulling linemen who come from the backside of the line of scrimmage.
The “counter trey” is a type of counter running play that uses misdirection as an attempt to catch a defense off guard. While three linemen (including the center), come off the line of scrimmage and block to one side, two linemen from the backside pull, attacking the defense on the opposite side. The running back at first fakes a move to the left, then takes the handoff and cuts to the right, following the trailing offensive tackle into the hole.
Some college teams with a mobile quarterback will often use the quarterback as the trailing blocker in place of one of the linemen. When this play is effective, it can demoralize and physically tire opponents on the defense, and helps mix up the running attack to provide the offense with more options and the defense with more guessing.
The counter trey was used extensively by Joe Gibbs and the Washington Redskins in the 1980s, but is originally attributed to Nebraska Cornhusker teams from the 1970s.