Buffalo traded Moulson to Minnesota at the deadline last season, then the Sabres signed him back in the off-season. That's the only time I can recall it happening ( I'm sure it's happened before though, this league has been around for 100+ years after all ).
I wouldn't count on Foligno and/or Letestu re-signing with us if we trade them. Some guys take that personally.
http://hfboards.mandatory.com/showthread.php?p=73376833
http://hfboards.mandatory.com/showthread.php?t=1522963
That's why you talk to them prior to the deadline. Tell them...
A)"We're not going anywhere this season so if we can get assets for you and then bring you back in the Summer, why not"?
B)"We will be trading you to a contender/team fighting for a playoff spot. You will have a shot at the Stanley Cup(if going to a contender) or you might have a chance at a Cup(if going to a bubble team)".
C)Maybe they won't say it, maybe they will. "By us trading you, we get worse as a team this season. It will improve our draft positioning".
Is it against the rules for a GM to tell a player of his plans, like, "hey Nick, here's the deal.. we wanna load up on some pieces and also give you a chance at a Cup this year, but we do intend on offering you a sizeable contract in free agency.."?
I would say no. Also, if it was how would the NHL prove you did this? You just tell them we wanted to extend him a but couldn't so we traded him. Then once free agency begin, we continued where we left off and reached a deal.
Also, if there was a rule, I think it would be like not being able to sign someone you just bought out. So they would have made a rule like, can't sign a player you traded in the previous season.
Heck, what if they have a gentlemen's agreement. Both sides reach a deal but don't sign it until free agency? Although huge risk by the player by doing this. Not because if JD/Jarmo backs out but if the player suffers a major injury.(Before anyone brings up Prospal and his agreement, that was between him and Howson. Not JD/Jarmo)