One of the AFL's premier intercept markers, Andrews had his effectiveness limited by Geelong's Jack Henry and GWS forward Max Gruzewski in consecutive losses over the last fortnight.
Voss, meanwhile, has performed notable defensive roles on Hawthorn's James Sicily and St Kilda's Callum Wilkie in recent weeks and got under his opponents' skin.
Fagan expects Voss will have Andrews in his sights when the ladder-leading Dockers visit the Gabba on Saturday in what shapes as a significant clash for both sides.
But he has no magic solution for the Lions' co-captain, who will likely attempt to man-up on Fremantle spearhead Josh Treacy.
"It's hard ... you can't move him. He's a back-line player and he's playing on an opponent," Fagan said.
"He's just got to fight through, be strong in the mind, back himself in and not be distracted by the attention.
"I thought he did it quite well last week, probably better than what happened against Geelong the previous week.
"It's just getting accustomed to it and backing himself in."
St Kilda coach Ross Lyon labelled Voss's tactics "bizarre" after the fiery forward got into several scraps with Wilkie and often played behind his opponent last week.
But Fremantle counterpart Justin Longmuir was pleased with Voss, who restricted Wilkie to just one intercept mark.
Despite that performance, Longmuir wouldn't commit to giving Voss the important Andrews match-up.
"We'll see," he said.
"We probably went to that last year (in round 23) and it didn't work as well as we would have liked."
A Voss-Andrews battle could be a key factor in deciding Saturday's contest, which will have top-eight ramifications for both sides.
Brisbane (6-5) have slipped to eighth as they chase a third straight premiership, while Fremantle (10-1) are one win clear in first place.
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