GREATER Western Sydney ruckman Tom Downie has been placed on the long-term injury list to deal with a mental health issue.

GWS revealed on Thursday that Downie has been struggling in recent months and had spent some time away from the club at various stages, so the move will allow him to concentrate on getting the support he needs.

The 23-year-old has played nine senior games for GWS in his five seasons with the club, with the athletic big man managing seven of those in the second half of 2015 after Shane Mumford went down with a serious ankle injury, and one last year when Mumford was rested against Essendon in round 13.

GWS footy manager Wayne Campbell said the club had been working with Downie and his family, his management, and the AFLPA, and the move is seen to be in the player's best interest.

“Tom’s been dealing with a mental health issue for a number of months and the club is doing everything possible to support him,” he said. 

“Tom’s welfare is our priority, and those closest to him all agree that the best course of action is for him to step away from the game. 

“Tom’s a very popular member of our playing group and he’s got the full support of the club.”

The Giants will now weigh up whether to elevate a rookie to replace Downie on the senior list, with former Fremantle midfielder Tendai Mzungu, and forwards Sam Reid and Daniel Lloyd available to be elevated. 

Mzungu is the likely frontrunner in a move that could open the door for a round one appearance against Adelaide on Sunday March 26.

With vice-captain Stephen Coniglio (ankle), Brett Deledio (calf) and Matt de Boer (hamstring) all injured and certain to miss games early in the season, and youngster Jacob Hopper (back) having played just a half of footy in the reserves last week, Mzungu's experience and versatility could play in his favour when Leon Cameron picks his best 22 to face the Crows. 

The 31-year-old arrived at the Giants in November after playing 102 games over six seasons with the Dockers, and gathered 22 possessions and kicked a goal in his only appearance of the JLT Community Series against West Coast. 

Reid kicked six goals from seven games after coming onto the senior list last season, while Lloyd is yet to debut for the club, despite some outstanding form in the NEAFL.