What happens to a player who is constantly offside in a match? Is there any rule or sanction for that?
Nothing. Every time it happens the defending team gets gifted possession in the form of an indirect free kick, which is punishment enough.
Football is played under the IFAB Laws of the Game. However, there are many unwritten "common law" elements (ie. customs and traditions) that are part of the game. It is generally expected that referees possess this tacit knowledge. In every competition I've ever played in, refereed or spectated, persistent infringement only applies to Law 12 (Fouls and Misconduct) and Law 14 (Penalty Kick) infringements.
The persistent infringement clause of Law 12 exists to allow referees to warn, caution, and then send-off players that are consistently committing infringements with the effect of preventing the opponents from playing. Since committing an infringement when your team has clear possession of the ball doesn't have this effect and only harms your own team, it would be very strange to consider it to be conduct worthy of a caution.
I provided some information on this in this answer illustrating this consensus among fellow referees.
It is worth mentioning that Law 12 mentions that a player may be cautioned for persistent infringement.
A player is cautioned if guilty of:
- persistent infringement of the Laws of the Game (no specific number or pattern of infringements constitutes “persistent”)
However, it is a general understanding amongst referees (think of it as common law) that players should not be cautioned for persistent infringement when the infringement only harms their team eg. taking a free kick to oneself, incorrectly taking a throw-in, offside. This forum thread on RefChat highlights this:
Are there any circumstances when you might caution a player for being persistently penalised for being in an offside position?
No it's a technical offence, a bit like persistently taking a throw-in incorrectly, which you wouldn't caution for either
Another way of thinking of it, is that he is only penalising his own team
Actually I don't see how the striker is doing anything wrong beside being offside
If you consider that he's interfering while being offside, than give the offside
If he does it again, do it again
If he does it again, do it again
Who is he harming beside his own team in this scenario ?
This is contrast to offences which actively harm the opponents' ability to play should and hence should come under the guise of persistent infringement. Examples of this include repeatedly fouling opponents, encroaching at a penalty kick forcing a retake multiple times, consistently holding opponents at a corner kick before the ball is in play.
I've also dug up some more information, in particular from Jim Allen, former director of US Soccer's national referee program. In this question and answer he considers the possibility of persistent infringement caution due to offside:
On Sunday I watched the FC Dallas vs. Denver Rapids where one forward got called offsides 5 times. I read online where someone was calling for a yellow for “persistent infringement of offsides”. I have never heard of this and I can’t find anywhere that I could justify a yellow for persistent infringement for being offsides.
I also would have to ask myself if I thought this yellow would help the game.
Please let me know if a yellow can be given here?
USSF answer (June 4, 2008):
It is perfectly legal to be in an offside position. The person who posted the suggestion you saw online is probably the person who asked us the very same question almost five years ago about high school soccer, to which we replied on October 23, 2003:
No, there is no such rule in soccer, whether at the high school level or in the . . . worldwide game of soccer. . . . Persistent infringement applies to any and all infringements of Law 12 and to some infringements of Law 14.
Considering that this part of the Laws of the Game has no changed since that answer was provided (and all of these answers provided by USSF are backed by FIFA/IFAB), it is safe to say that this custom still would apply.
Finally, the following question asked on asktheref.com also points out that referees should only consider Law 12 and Law 14 offences when considering persistent infringement:
Excerpt from the question:
... she was in offside position and involved in the active play all 8 times (I didn't include the times she was simply in offside position and not in the active play, and therefore not penalized), and the reason I ask is because the wording for PI doesn't specify which laws someone must break to be cautioned for PI. I too believe that Law 12 would be the basis for PI, and I've always worked that way, but I brought it up because it seems that in this regard ...
Excerpt from answers:
In America the referee is governed by US Soccer's policy and that is published in Advice to Referees on the Laws of the Game. The policy is persistence applies to Law 12 and in some instances Law 14.
Still can't be PI. In US only violations of LAW 12 and, as ref Fleischer corrects me, Law 14. Besides, PI is there to punish a player for disadvantaging an opposing team by persistent fouls that don't warrant a caution. In this case, she's helping the other team out. The Spirit of the Law would forbid a caution in this instance.
This "Spirit" that is spoken of is now a formal part of the Laws of the Game (as of 1st June 2016).
Decisions will be made to the best of the referee`s ability according to the Laws of the Game and the spirit of the game and will be based on the opinion of the referee who has the discretion to take appropriate action within the framework of the Laws of the Game.
It is certainly not appropriate, nor a sensible use of discretion to caution a player for doing nothing more than harming their own team.
As far as the ref is concerned, there is nothing wrong with offsides. It penalizes the offensive team for trying to "cheat" their way past the defense. There's an entire defensive strategy called "the trap" which relies on putting players offside.
The player might get reprimanded by his coach, get substituted out, etc... Team B is more than happy if Team A is constantly offside as it gives possession back to Team B.
Law 12, Section 3 states that
A player is cautioned if guilty of [...] persistent infringement of the Laws of the Game (no specific number or pattern of infringements constitutes “persistent”)
The player would be cautioned, and if the pattern of offending didn't stop, would receive a second caution and be sent off.