NEIL HARRIS said Millwall made a "statement of intent" this week by tying Aiden O'Brien to the club until June 2019.
O'Brien, 22, signed a two-year deal with the Lions last summer, but the club promised him and his dad at the time a new deal would be on the table if his form merited it.
And the former Republic of Ireland international has responded to the challenge with ten goals so far this season. He has also shown his versatility by playing on the wing.
That has led to some speculation linking him with a move to the Premier League, though O'Brien has consistently said he is happy and settled at Millwall.
Harris says the player has been "rewarded" for his from and attitude and that the move is a signal to all of Millwall's young players that success on the pitch will be recognised.
"It's brilliant news, brilliant for the boy. It's a statement of intent from the club that we want to tie down our best young players to the club," Harris stressed.
"Aiden's been rewarded for hard work. All we've done is give the boy some stability, some focus away from press speculation, the short-termism when someone does well in a short period of time.
"As we've said all along, young players aren't for sale at this club. They're here to grow and make us a better club.
"As a club we're taking short-termism out of it to give our young players an opportunity to flourish over a longer period of time.
"What we're doing with Aiden just highlights that even further, that we've got faith in our young players.
"Aiden signed an improved contract in the summer because he'd been on the same contract for three-and-a-half years.
"He came into the team at the end of last season and did really well for us. He's gone from an U21 player to a first-team regular and he's grown up a lot in that time.
"We rewarded him in the summer and we decided, as with all our young players, if they do really well we'll tie them down to long-term deals.
"At this club you get rewarded for doing well, not for past history, not for something you've achieved at a different club. It's about what you do for this club and what you bring.
"If my players do well for me I want to reward them with longer contracts that bring stability to family life, to living location and obviously, for the youngsters coming through, financial rewards."