MILLWALL beat the Friday midday deadline to sign Ryan Woods – with Shaun Williams starting a three-game ban.
Woods, 26, could go straight into the match-day squad against Reading after signing on loan from Stoke. The Lions had hoped for a reduction in Williams' suspension after his red card against the Potters last weekend, but the club's appeal failed.
Lions boss Gary Rowett is considering whether to play a four-man or a five-man defence against the Royals.
The Lions have lined up in a 5-2-3 formation in their last six away games when they have been unbeaten and conceded just three goals.
Rowett started with five at the back in the last home league game against Luton but withdrew Alex Pearce three minutes before the break with the side 1-0 down, before a second-half fightback secured a 3-1 win.
Meanwhile, Aiden O'Brien returned to training on Monday after missing the 0-0 draw at Stoke last Saturday with an ankle injury.
Ben Thompson is out, along with Ryan Leonard, who has started doing running exercises as he recovers from knee and hamstring problems. Billy Mitchell is in contention to start.
Frank Fielding could be the match-day squad for the first time since the opening day of the season after he played against Charlton under-23s on Monday. Back-up stopper Luke Steele's return to Nottingham Forest is imminent after his loan spell.
Rowett was full of praise for Steele.
"I'm not sure on the exact date, I think it might be after Reading," Rowett said. "Steeley's been great, he's a brilliant, brilliant character and his performances in training have been absolutely fantastic.
"Because he wants to play football, if he goes out on loan somewhere else then someone's going to get a top-drawer character and goalkeeper.
"But he's not our player, he wants to go and play, so our priority has to lie with Frank. When we feel Frank's fully fit, and I'll speak to LT [goalkeeping coach Lee Turner] about it this week, there's then the debate about whether he goes on to the bench for Saturday's game.
"We'll have a discussion and that will be based on how he got through the game and how he felt."
Reading have enjoyed just as impressive a resurgence under Mark Bowen as Millwall under Rowett. When Bowen was appointed manager – following his role as sporting director – on October 14 Reading were 22nd after just one point from their pervious six games.
Reading have lost just three times in their last fifteen Championship fixtures and are on a seven-game unbeaten run after last Saturday's 1-1 draw at home to Nottingham Forest.
In a crowded mid-table to the play-offs the Royals are in fourteenth place but just six points off sixth.
Reading and Millwall are fifth and sixth in the form table over the last fifteen games, the Royals having picked up 28 points to the Lions' 27. Bowen's side have scored 23 goals to Millwall's 22 in those games, and conceded just twelve to Rowett's side's fifteen.
Possible Millwall starting XI: 4-4-2: Bialkowski; Romeo, Hutchinson, Cooper, M Wallace; J Wallace, Woods, Molumby, Mahoney; Bradshaw, Smith.
Match odds: Millwall 4/6 Draw 12/5 Reading 7/4
Last meeting: Championship (November 2): Reading 2-1 Millwall (Obita 9, Baldock 37; J Wallace 63)
Image: Millwall FC