Jane Slater of NFL Media reports that the initial diagnosis is a partial avulsion of his hamstring tendon, which is the tendon partially tearing off the bone. The recovery time typically is more than four weeks, which is the minimum stay required for an injured reserve stint.
Prescott is seeking other opinions, per Slater, before the Cowboys make a decision on whether to place the quarterback on IR. It is not yet known whether he will require surgery.
In some cases, the injury is allowed to scar over, repair and then strengthen. It is unknown where in the hamstring the injury is.