Code this, code that. Nobody is quite sure exactly what it is in the NHL.

But here was the code as described by Marty McSorley, when he came to the Rangers from the Kings in 1996 after having been Wayne Gretzky’s teammate for 11 seasons in Edmonton and Los Angeles:

“Everybody who is on the ice with Gretz has to be willing to take a game misconduct penalty at any time.”

So here is Code Blueshirt: Everybody who is on the ice with Rick Nash from this moment forward has to be willing to take a game misconduct at all times.

Nash, who has missed 17 games with the concussion he sustained on a shot to the head from Brad Stuart in San Jose on Oct. 8, will decide Tuesday morning whether to make his return that evening at the Garden against the Bruins, or to defer it until Thursday night in Dallas so he can get in one more full-contact practice on Wednesday before rejoining the fray.

When No. 61 does return to the ice, his teammates must play with the collective mentality that a blow delivered against Nash is tantamount to a strike against the Rangers’ franchise itself, and will be dealt with immediately.

Nash can choose whether to return against the Bruins or Stars, but he can’t, won’t and never would hopscotch his way through and around the schedule once he deems himself fit. If that means Milan Lucic, Zdeno Chara and the Big Bad Boston minefield present the first challenge, then that’s the way it is.

Nash, you’ll recall, suffered his first concussion of the calendar year in Boston on Feb. 12 when Lucic rode No. 61’s head into the glass while finishing a check. The feared Bruins winger then threw his considerable weight around during the second round of the playoffs, muscling Nash to the ice in front of the Rangers’ bench before appearing to taunt him in a memorable confrontation during the third period of Game 5.

The Rangers cannot allow this sort of thing to happen again. They cannot allow their franchise forward to be abused. They must be willing and able to respond at the first sign of trouble.

Yes, it is true — I believe and have posited for years the NHL should ban fighting, but that does not mean I recommend any team in the league should unilaterally disarm itself.

It is impossible to define what constitutes a deterrent in the 21st Century NHL, but reviewing the rosters of the Bruins, Blackhawks, Kings and Sharks would probably be a good start. They are big, strong, and as mean as required. Nobody trifles with these squads. Nobody messes with them. The Rangers aren’t in that class.

Two years ago, the Blueshirts played with a pack mentality best personified by Brandon Prust. But that didn’t stop Ottawa’s Chris Neil from his head-hunting excursion on Brian Boyle in Game 5 of the first round of the 2012 playoffs. So there is that.

I am not suggesting the Blueshirts hire a goon or a headhunter to ride shotgun for Nash, who likely would recoil at the suggestion he requires special protection. But he does. Indeed, there are 7.8 million reasons a year for that; 7.8 million reasons for general manager Glen Sather to fortify the roster.

The threat of retaliation may or may not equate at some point to deterrence, but when The Big Easy is on the ice, his teammates all must be willing to adopt the McSorley Code and take game misconducts if necessary.

That must become Code Blueshirt, and whether against the Bruins or Stars, or anyone else, it must imply an eye for an eye. Silence of the lambs is not an option.