ADELAIDE assistant coach Matthew Clarke says Ivan Maric will be under pressure to retain his mantle as the club's No.1 ruckman this season following the arrival of former Carlton big man Sam Jacobs and an adjustment to the AFL's interchange rule.
In October, the League announced that benches would be downsized to three players and one substitute in a bid to curb the escalating number of rotations during matches.
Key officials, including Western Bulldogs coach Rodney Eade, predicted the new rule would spell the end of the second ruckman, but it didn't deter Adelaide from chasing Jacobs as a replacement for outgoing tall Jon Griffin during trade week.
Though Maric has missed just five games since cementing his spot at the Crows in 2008 and was a member of the senior leadership group last season, Clarke said Jacobs and a renewed Brad Moran would challenge the 25-year-old.
"Ivan's done the majority of work in the first ruck role over the last couple of years and was the No.1 ruckman in the last game of last season. Incumbency counts for something but your form is only really good for one or two games," Clarke said.
"What Sam's done so far has been impressive and we've also got Brad Moran, who didn't play at all last year because of injury. We've pretty much got two new ruckmen into the system this year and Ivan will be under pressure from those guys.
"I'm sure they'll all get opportunities throughout the NAB Cup and whoever performs the best over the that period and on the track will get the first crack."
The new interchange rule could suit former first-round draft pick James Sellar and utility Shaun McKernan, who have struggled for regular selection in recent seasons.
Sellar has played 16 games for Adelaide as a pinch-hitting ruckman/forward, while McKernan made his debut in round 14, 2009 before breaking his arm at training the next week.
McKernan, at 196cm and 100kg, has been described as having 'midfield-range' qualities and Clarke said he was imposing himself on pre-season training.
"Shaun can play either as a forward or a ruckman and he's also played a fair bit as a defender in the SANFL, so he's got that versatility which may well come to the fore with the change in the interchange rules," he said.
"He's a good prospect. He hasn't done anything [at AFL level] yet, but it looks like he might be able to and I'd be surprised if we didn't see some of him in the NAB Cup."
Another developing ruck prospect, James Craig, is unlikely to take part in the NAB Cup as he recovers from a hamstring injury unrelated to the one that prematurely ended his 2010 season.
Clarke and ex-Essendon assistant coach Scott Camporeale have taken charge of the Adelaide midfield and are likely to introduce some different faces, with Jason Porplyzia, Patrick Dangerfield and Andy Otten joining their group at training on Thursday.
"Andy played midfield as a junior and has attributes, which certainly make him capable of playing in there ... but sometimes you forget that he hasn't played footy for over 12 months and we need to be mindful of that in our expectations," Clarke said.
