ATR 5.8 says that once a player who has left the field because of blood or an equipment problem has fixed the problem the player may return “even if play is continuing.” Guide to Procedures, in the section on the Fourth Official and equipment problems also talks about notifying the referee the player is ready to return, “whether during play or at a stoppage.” I also found a 4/23/2001 position paper, Players Temporarily Off the Field Involvement of Fourth Official, that says for bleeding, blood on the uniform, or illegal equipment, the referee should grant permission to return “as soon as possible without waiting for a stoppage of play.”
How are the instructions in these sources regarding equipment problems squared with Law 4 which clearly states that for any infringement of this law, “the player is only allowed to re-enter the field of play when the ball is out of play”?
USSF answer (February 4, 2008):
Short answer: In a game situation, most referees should do it the way the situation is covered in the USSF literature.
Longer answer for this situation during a game: The Federation has officially recognized that a player ordered off to correct an equipment problem can return to the field during play if he (or she) receives the referee’s permission and if the equipment problem has been corrected (and verified by the assistant referee or fourth official), assuming this authority has been delegated by the referee. If the referee has not delegated the authority, then only the referee can inspect and the player must wait for a stoppage to return to the field.
Longer answer for a test: Since the literature defines policy for referees in this country and since any test a referee in this country might take would be solely guided by such advice, saying the player could return during play (if the specified conditions are met) would be entirely correct.
Only our FIFA referees taking a FIFA-sponsored test would have to remember that our guidance on this differs from the strict requirements of Law 3. This divergence has been in place from the very first moment that FIFA recognized the ability to return to the field during play for all other situations where the player has received permission to leave or been ordered off under Law 5 — we believe that the principle underlying FIFA allowing a player to return during play under all these other scenarios should apply equally to being off the field to correct equipment.