DEFENDER Harry O'Brien will miss four weeksafter suffering a dislocated shoulder against Melbourne on Monday.
O'Brien, 20, sustained the injury in amarking contest deep in defence during the first quarter.
He will undergo rehabilitation over thenext month after medical staff deemed surgery wasn't necessary.
The Brazilian-born O'Brien had beenenjoying an excellent season for Collingwood, having played all 11 matchesafter being permanently elevated to the senior list at the end of 2006.
Up until 2007, he had played 13 seniorgames as a rookie-listed player who was intermittingly upgraded to senior liststatus owing to long term injuries to other players.
