Kerr had scans on his tight left hamstring this week, which revealed bleeding similar to the injury key forward Jack Darling was able to play through two weeks ago.
Cox hurt his left ankle in a ruck contest against the Brisbane Lions last Sunday and was managed in the second half, but coach John Worsfold said he had recovered well this week.
The coach said both players would be put through their paces on Wednesday afternoon at Patersons Stadium where their Derby fate would take shape.
"There's a fair bit of work to do today whether he (Kerr) is going to play or not - he's certainly not ruled out and we'll see how he feels when he runs around today," Worsfold said on Wednesday.
"We assume they're in until they're ruled out … they don't need a fitness test if they run around no worries.
"It will depend on today. We won’t name them if they’re not really a chance to play. It's unlikely that we would do that."
Kerr experienced tightness in his left hamstring from the start of last Sunday's win over the Lions and was taken out of the game before half-time as a precaution.
Worsfold said the club was still trying to work out "exactly what's wrong with him" and would not take any risks as the club's top-four chances go on the line against Fremantle.
"'Kerry' said he was tight from the very start of the game and he didn't really want to open up and hit any sort of speed," the coach said.
"He was a bit concerned. He's got a history of how his hamstrings feel prior to doing his really bad injury a few years ago. That was playing on his mind from the very start of the game.
"He was basically pacing himself until he got to the point where he didn't want to take the risk anymore."
The Eagles face a selection decision on captain Darren Glass's replacement after the full-back accepted a one-match ban for rough conduct.
Worsfold said he would consider whether a like-for-like replacement was needed to combat a Fremantle forward line that would include marking targets Matthew Pavlich, Kepler Bradley and Chris Mayne, with ruckman Jon Griffin rotating forward.
"(Jacob) Brennan went out of the side last week but he has been going pretty well for us," Worsfold said.
"Ash Smith, Mitch Brown, Lewis Stevenson is in really red-hot form in the WAFL, so we've been really pleased with how he's going.
"Those guys we'll have a look at."
Meanwhile, veteran Andrew Embley is likely to play at least one more match in the WAFL as he returns from shoulder surgery.
Worsfold said it was possible the 2006 Norm Smith medallist would play at AFL level as a substitute in the coming weeks.
"That doesn’t stop him from coming into the side and playing a full game first but that’s unlikely to be this week," the coach said.
"He had a pretty good hit out last week and at some point we will give him a lighter week. That’s the week we may use him as a sub."
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