ADELAIDE will buck the trend of targeting out-of-form Western Bulldogs defender Jason Johannisen in Friday night's encounter at Adelaide Oval.

Opposition teams have successfully applied physical pressure to negate the influence of last year's Norm Smith medallist.

Johannisen has struggled to provide his usual attacking bursts off half-back, averaging just 13.75 possessions in his past four games compared to 25.3 in the first 10 rounds.

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"I've seen Johannisen tagged directly, one v one, but we've tended not to do that," Crows forward Josh Jenkins told

"We think the best way to make a defender worry about someone else is to play really well and make him defend.

"We'll have an eye on him and understand how good he can be if you let him run and carry the ball, but for the most part, we'll ask him to defend like the other five or six defenders for the Bulldogs."

Jenkins did his fair share of defensive duties in last weekend's 12-point win against Carlton, racking up a career-high 13 tackles.

"It's an expectation as forwards, irrespective of your size and shape, that you get involved in defence and go after guys when they've got the ball," he said.

"We identified Kade Simpson and Sam Docherty were often influential whenever Carlton played quite well, so just tried to get after them.

"(Thirteen tackles) is not something I expect to do every week, but I'd like to lay one or two (tackles) a quarter."

Jason Johannisen was targeted by the Eagles in round 15. Picture: AFL Photos

It's been a weird old season for Jenkins.

Coming off 62 goals last season, the 28-year-old fractured his ribs in the round two win over Hawthorn at the MCG.

He struggled when he returned to the side, but after a confidence-boosting stint in the SANFL, has booted 14 goals in his past five games, with four bags of three.

"It's been more consistent than last year," he said.

"I haven't had the highs I had last season, but my tackle count is good, I'm taking more marks, winning more of the ball and my ruck work's been pretty solid as well. "I understand I can provide a little bit more up front, would like to win a few more contests inside 50 and help the team in that respect."

The absence of link-up forward Tom Lynch for the second straight week as he recovers from viral meningitis changes the structure of the Crows' attack.

"We've got plenty of guys who can fill in," Jenkins said.

"Lynchy does it with prediction and reading the game, and other guys such as Riley Knight can do it with a bit of speed.

"We're not going to have an exact replica of Tom Lynch, a guy that can do it all game, but we can share the load."