(a) Any contestant absenting himself from a show in which he has signed or has been signed by his duly licensed manager to appear, without a written valid excuse or a certificate from a commission physician in advance in case of physical disability,is subject to disciplinary action.

(b) Any boxer who files a certificate from a commission physician stating that he is unable to fulfill a contract on account of physical disability shall on being restored to the eligible list, fulfill his contract with the same opponent or a suitable substitute at the club specified in the contract within a reasonable time, such period to be set by the commission, unless the boxer is released from the contract by mutual agreement.