First, the Blues believed it was in no one's best interests for Henderson, who has been playing below par recently, to get injured - since this would potentially hurt Henderson's deal with his new club, and also Carlton's return in any trade.

Lachie Henderson's early call has rekindled the debate about loyalty in footy

The second factor behind Carlton's ground-breaking decision was the Blues' view that it was better to invest time in players who would be at the club next year - and give that player or players - an opportunity. If Henderson was leaving, the Blues felt there was little point in him playing - and obviously Carlton is not competing for finals.

Carlton has been trying to sign Henderson, 25, this year. The Blues want the best possible draft return for him, and any deal with the Cats appears likely to involve a first-round pick.

Henderson and his manager Tom Petroro met Carlton's football boss Andrew McKay last Tuesday and informed him that the player, who is out of contract but not a free agent, was seeking a trade.