IN-FORM ruckman Mark Jamar has signed a new contract keeping him at the club until the end of the 2012 season.

Affectionately known as ‘Russian’, Jamar’s two-year deal coincides with his finest AFL season.

He has been widely regarded as one of the AFL’s most improved players this year and is also being viewed as a potential All-Australian.

List manager Tim Harrington said Jamar had become an important member of the line-up.

“Mark has become a very important cog in our team,” he told melbournefc.com.au.

“We’ve been given a great advantage through his ruck work.

“With a younger midfield group, it’s vital that we’ve got some physical presence in there and Mark provides that for us."

Originally from North Adelaide, Jamar debuted in 2003, after coming to the club as a rookie list player.

He has played 85 matches, including all 12 this season, after an injury-interrupted 2009.

Jamar showed glimpses of his 2010 form last year - he had 31 hit outs against Collingwood in round 11 and kicked five goals against Carlton in round 21 last year - but has produced consistent performers and been injury-free.

This season he is averaging 29.41 hit outs per match.

He also notched up a career-best 25 disposals against Collingwood on Queen’s Birthday.