North Melbourne trio in Ross Lyon's sights for Sunday's clash TOUGH TASK: Andrew Swallow could have a date with Fremantle's Ryan Crowley on Sunday. FREMANTLE coach Ross Lyon has earmarked trump North Melbourne trio Brent Harvey, Daniel Wells or Andrew Swallow for special attention in Sunday's clash in Perth. Lyon has revealed that gun tagger Ryan Crowley will be assigned to one of the star Roos playmakers as his miserly Dockers continue an imposing push into their most genuine premiership potential in Fremantle's two-decade history. Crowley, 29, has evolved into one of the AFL's most reliable defensive run-with exponents and each week invariably takes an assignment from Lyon to curb influence from an opposition's most damaging prime mover. Swallow averages 24 disposals a game so far this season with Wells collecting around 21 and the incomparable Harvey has tallied in the region of 22 an outing in his past five engagements since completing his six-week suspension to start his 2013 campaign. "He'll get one of - you're looking at Wells, Harvey or Swallow - and he'll get another big task for the weekend and it would be nice that he would keep it going," Lyon said on Perth radio station 6PR. The hard core Dockers coach described North Melbourne's best performances at spasmodic times of this season as "elite" ahead of a confrontation when the Roos will all but surely be out of finals prospects with another loss. North suffered a horrid late fadeout and demoralising four-point loss to West Coast in Perth a month ago, when cult figure ruck force Nic Naitanui took a whopping contested pack-mark and booted a set-shot goal after the final siren. The Roos have copped four almost season-defining losses by a combined total of just 10 points in their sequence of near-misses ahead of resuming from their Round 12 bye, with the road trip to confront the most defensive unit in the business. The Dockers concede an average of only 70 points a game under Lyon's stringent defensive mechanisms, while North has maintained healthy scoring powers with around the fourth-best weekly average of 104 points at each engagement. "Their best has been elite," Lyon analysed. I think they've probably only had one disappointing game by their standards, which was probably the Gold Coast (15-point loss) which is their last game. But up until then they'd played the elite games in the competition and headed them and been in close games. As a young group I think they're right on track. Lyon expects North's heavy internal scrutiny from within their own football management over last week's bye as well as the AFL industry, to potentially spark the Roos into a desperate approach to resurrect their flagging finals hopes on Sunday. North would need to win at least eight and possibly as many as nine of their last 11 games to crash back up the congested AFL ladder to finish in the final eight in September. In the next six appointments the Roos confront the Dockers and other possible finalists Richmond in Round 15 and Carlton a fortnight later both at Etihad Stadium. Other engagements for North appear potential vital victories against Greater Western Sydney at Etihad in Round 14, Brisbane at the Gabba in Round 16 and beleaguered Melbourne at Etihad in Round 18. "They've been put under a fair bit of scrutiny and the last time here against the Eagles, they probably had it (a win) pinched off them," Lyon assessed. We understand what's coming over. It's going to be quite difficult to get the points. Lyon and his support staff are expected to rule later this week whether exciting small forward Michael Walters resumes after the opportunist goal-shark has missed the past month with an ankle problem. Walters, 22, has booted 19 goals from his eight outings this season and looks more likely to resume than veteran stars Matthew Pavlich and Aaron Sandilands. Pavlich, 31, resumed full training this week after Achilles surgery almost two months back, but is expected to be sidelined for at least another fortnight before a comeback. Sandilands, 30, has not played a senior game this season on the back of a horror run of hamstring problems over last summer and surgery to remedy his woes.