NATHAN Grima is sick of being injured. Bloody sick of it, in fact.

But in a week when Mark LeCras' and Brent Macaffer's 2012 seasons ended before they began, Grima realises things could be worse.

Grima suffered a high-grade medial ligament strain in his left knee when teammate Jack Ziebell fell across him in the opening half of North's round one NAB Cup game against Richmond last Friday night.

The injury is expected to sideline him for four to six weeks. But Grima appreciates it's a far brighter prognosis than that facing Eagle LeCras and Magpie Macaffer, who will both almost certainly miss the whole season after rupturing anterior cruciate ligaments last week.

"I've had my fair share of bloody injuries. The only time I get interviewed is when I get injured and I've had more than my fair share of interviews lately," Grima told kangaroos.com.au light-heartedly on Tuesday.

"But as frustrating as it is, you only have to see Brent Macaffer and Mark LeCras do their ACLs and, as much as you feel for them, you're rapt not to be in the same boat."

Grima knows what it's like to go through a knee construction. He ruptured his right ACL shortly after he was selected by North Melbourne in the rookie draft in late 2007.

Armed with this knowledge, Grima was confident he hadn't ruptured his ACL last Friday night.

"I knew it was pretty serious. Jack Ziebell is a big boy and he hit me at high force," Grima said.

"But it was a different pain to when I did my ACL, so I wasn't too concerned."

Luck is a relative thing, however. So although Grima emerged from last week in better shape than Macaffer and LeCras, his luck over the past 18 months has been nearly all bad.

Last January, he finally succumbed to a debilitating back injury that had ruined his 2011 pre-season, undergoing surgery to removed a bulged disc.

Then, just as he was getting back to form and fitness, he broke a finger midway through the 2011 season.

Before last Friday night, Grima's luck had mostly held this pre-season. He completed an outstanding training camp in the high-altitude of Utah last October and, apart from minor lower back soreness before Christmas, scarcely missed a session.

Now his pre-season goal of playing in round one for the first time in his AFL career is in jeopardy.

Grima's left knee will be in a brace for the next two weeks but, having recommenced swimming on Wednesday, he is hopeful his strong fitness base won't drop off significantly.

However, having rushed back from his back surgery by round two last season and subsequently struggling for fitness and form, Grima is not going to get caught up in the lure of playing in round one - although he admits North's Saturday night season-opener against Essendon is a game he'd love to play in.

"I'll take a more cautious approach this time around," Grima said.

"I've just got to get myself right, whenever that is."

In addition to restricting him to 42 games in his four seasons at North, injuries have also hurt Grima's leadership prospects.

In the lead-up to last season, coach Brad Scott touted Grima as a potential future captain. But when Brent Harvey stepped down earlier this month, Andrew Swallow got the nod as his replacement, while Grima was not named in the Kangaroos' five-man leadership group.

Grima said he had never harboured strong leadership aspirations and was not disappointed to be left out. Self-deprecating to a fault, Grima also downplayed his leadership credentials.

"When Brad made those comments I was playing a lot better footy, which helps you have a bigger impact on the group - it feels like a lifetime ago," he said.

"Now my main concern just has to be getting myself right and playing the best footy I can.

"A bit of luck would be nice; I've paid my injury dues I reckon. But in the scheme of things a four-week knee injury is pretty minor compared to some of the other things that are going on in the world."

Nick Bowen covers North Melbourne news for AFL.com.au. Follow him at Twitter @AFL_Nick.

Toyota AFL Dream Team is the only fantasy football competition where you can follow the scores LIVE during the NAB Cup. Register your team and see how your players are shaping up before the start of the Toyota Premiership Season.