Neil Harris admits he will make changes for Tuesday night's trip to Reading and has encouraged those selected to "stake their claim" in the Carabao Cup Second Round tie.
The Lions boss made nine changes for the First Round fixture against Stevenage earlier this month, resulting in a 2-0 win over the League Two side.
Millwall have since endured a taxing run of four games in ten days, culminating in the goalless draw at Bristol City on Saturday.
"I will make changes to the team that played at Bristol, definitely," Harris told millwallfc.co.uk
"Some players have played a lot of minutes recently and there are others that haven't played much at all."
Striker Tom Elliott will be assessed prior to kick-off as he looks to shake a bout of illness that struck during Saturday's fixture at Ashton Gate.
"There was a bit of illness in the camp," Harris added.
"A few of the boys were throwing up at half-time at Bristol City so they are being monitored and we will see how they are when it's time to pick a team."
And while the manager says progressing in the Carabao Cup is tonight's main objective, he also wants players to view tonight's tie as an opportunity to secure their place in Saturday's squad for the visit of Norwich to The Den.
"I'm looking forward to the trip to Reading and giving people a chance to impress. Not just to get minutes under their belts but to really stake a claim and secure their place in the team."