The hosts come into this clash on the back of a goalless draw away to Barnsley, while Millwall suffered a 2-0 home defeat to Blackburn Rovers.
Goals in each half, from Bradley Dack and Sam Gallagher, gave the Lancashire outfit all three points.
That stalemate left Derby County in the 18th spot, seven points from safety. Millwall are relatively comfortable in mid-table, having accrued 45 points from 36 games to date.
After a run of four matches without a win, including Wednesday night's goalless draw away at Barnsley, Wayne Rooney and his Derby squad will be looking over their shoulder at the possibility of a relegation scrap.
The Rams are currently seven points clear of the bottom three, although 22nd-placed Rotherham United have three games in hand.
Rooney's side have a challenging run ahead for the rest of this campaign, with Sheffield Wednesday on the final day of the season their only opponent who sit below 15th position.
On home soil, Derby have improved defensively in recent weeks, shipping just four goals in their last nine games at Pride Park, before conceding 13 times in their first eight home league matches in 2020-21.
Victory on Saturday would be their first of the month and could move them up one place above rivals Nottingham Forest into 17th position.
Millwall suffered their fourth home league defeat of the season as they were beaten 2-0 by Blackburn Rovers last weekend.
The Lions failed to score at the Den in a Championship game for the seventh time this season.
The result has seen Rowett's side slip down to 11th in the table, 12 points behind the playoffs, and 14 points clear of the relegation zone.
Millwall head to Pride Park with the seventh-best away record in the division, accumulating a total of 24 points from their 17 games on the road.
After failing to score in their last three matches, Derby manager Rooney may decide to name Martyn Waghorn in his starting lineup alongside top goalscorer Colin Kazim-Richards, which could see Lee Gregory drop to the bench against his former club.
Winger, Kamil Jozwiak, who has found the net just once in 31 league appearances this season, could make way for recruit Patrick Roberts, on loan from Manchester City, who was an unused substitute against Barnsley.
Millwall boss Rowett is unlikely to make too many changes from his starting lineup, despite losing against Blackburn last weekend.
The central midfielder, Ben Thompson, who was an unused substitute in the last game, could be reinstated into the lineup, at the expense of Billy Mitchell.
Jon Dadi Bodvarsson, Jed Wallace and Mason Bennett are set to form their front three once again, although target man Matt Smith will also be pushing for a starting spot.
Derby County Predicted XI (4-4-2): Kelle Roos (GK); Lee Buchanan, Teden Mengi, Matt Clarke, Andre Wisdom; Kamil Jozwiak, Graeme Shinnie, Max Bird; Jason Knight, Colin Kazim-Richards, Martyn Waghorn.
Millwall Predicted XI (4-3-3): Bartosz Bialkowski (GK); Scott Malone, Alex Pearce, Shaun Hutchinson, Mahlon Romero; Billy Mitchell, Ryan Woods, Shaun Williams, Jed Wallace; Mason Bennett, Jon Dadi Bodvarsson.
Ones to watch
Experienced striker Lee Gregory has joined Derby County on loan from fellow Sky Bet Championship side Stoke City at the beginning of February 2021.
During five successful seasons with the Lions, Gregory made 238 appearances and scored 77 goals, including a hat-trick in a 3-3 draw against Derby in April 2015, and he sits eighth in the list of all-time Millwall’s goalscorers.
He didn't have his best of games against Barnsley, so will look to avenge this against his former club. Gregory has a strong determination to battle away with defenders, even with his back to goal. The 32-year-old frontman likes to get hold of the ball, drawing in the opposition to foul him, winning free-kicks in doing so. He wasted a great chance when his heavy first touch allowed Collins to make a block in the game against Barnsley, so will be trying to get on the scoresheet in this fixture.
Mason Bennett joined Millwall on loan from Derby County until the end of 2019/20 season on 30th January. After an impressive loan spell, Bennett's loan move was made permanent in the 2020 summer transfer window.
The 24-year-old likes to receive the ball into his feet and will look to drive at the Rams defence. Derby should be aware of the former England Youth international's dribbling ability as he looks to get forward whenever possible and supply the ball to the target man.
This will be the 60th meeting between the two sides and their head-to-head records are almost identical.
Derby have a slight advantage with 23 wins and 14 draws to their name. Meanwhile, Millwall were victorious on 22 previous occasions.
The Lions lost last time out against Derby as Jason Knight's effort was enough to seal a slender 1-0 victory for the Rams in early December. Rowett has also lost his last two meetings with his former club and will be hoping to avoid another defeat on Saturday.
The home team will be seeking a victory on home turf to steer further clear of the dropzone.
Millwall have also been inconsistent, with a run of one win from their last five games seeing them lose their previous promotion hopes.
Derby County form guide: D-L-L-D-W
Millwall form guide: L-W-L-D-D
How to watch
Kick-off: 15.00 GMT, Saturday 13th March
The game will be available for both sets of fans from either club's website, with Derby using their own service RamsTV, whilst Millwall will be streaming the game on iFollow. Passes available from team websites.