MELBOURNE announced on Wednesday night that ruckman Mark Jamar was placed on the long-term injury list and promoted rookie Jake Spencer to the senior list, as his replacement.

Jamar’s injury is a setback for the Demons, who have been forced to place him on the long-term injury list after stress fractures in his foot did not heal as expected. The club is hoping he will be available in eight weeks.

The 19-year-old Spencer is the tallest player on Melbourne’s list at 203cm and has played in all four NAB Cup/NAB Challenge games this year.

Coach Dean Bailey said Spencer, selected with pick No.35 in the 2007 rookie draft, had the potential to excite.

“'This is a good reward for Jake.  He has been one of the players who has really impressed since we returned to pre-season training,” Bailey said.

“He’s a young ruckman who - with some experience - can be really exciting for us.”

In other injury news at the club, defender Jack Grimes will miss three to four weeks after developing a stress fracture in his lower back.

Bailey said the injury was a disappointment to the club but was hopeful he would be available for selection soon.

“Jack has completed a full pre-season, and has worked incredibly hard throughout,” Bailey said.

“We are hopeful that Jack will respond well to the treatment, and will be available for selection in three to four weeks.”

Once Grimes has completed a two week rehabilitation phase, the aim is for him to return to training in preparation to play.