Arnason is set for two weeks out with a bruised shoulder whilst loanee Devitt has gone back to Hull City with a hamstring problem.
Boss Steve Evans is also missing David Noble (ankle) with Kieran Agard facing a fitness test.
Daniel Nardiello could be recalled into the starting line up after the 1-1 draw at Fleetwood in midweek.
Evans, who has a lengthy absentee list, told Radio Sheffield: "We're only looking for players who can give us something different and better to what we already have.
"We've come a long way in four weeks but we've got a long way to go in the next eight until the January transfer window. We're not totally satisfied with the way we're playing at the moment but it's a work in progress.
"They're the in-form team in the league at the moment. They've been quite outstanding recently."
Daggers boss John Still is without Josh Scott (knee) but Billy Bingham is available.
Micky Spillaine is an injury doubt whilst Kevin Maher serves a one game suspension after his red card at Oxford.
The home side have lost just one of their last nine in League Two whilst the Millers have won four of the last five, meaning an entertaining game should be in store.
Fans without a ticket can pay on the gate with the clubhouse at the ground open from 11am, serving beer, hot food and showing Sky Sports.