LEE Gregory could return for Millwall when they face Braintree Town in the second round of the FA Cup at The Den on Sunday.
Gregory was due to train this week having missed the Lions' last two games with a back spasm problem.
Sid Nelson and Shaun Cummings are also in contention after both played in the U23s' 2-1 win over Coventry City on Monday.
Steve Morison and Jamie Philpot are still out, and the game is likely to come too soon for centre-back Shaun Hutchinson.
Millwall boss Harris is expected to pick a strong side this weekend as he will have the opportunity to rest frontline players against Wycombe in the last 32 of the EFL Trophy next Wednesday.
Aiden O'Brien, who started on the bench before coming on to grab a 92nd-minute winner at Bury last weekend, could be restored to the starting XI and he stressed no one is taking progression to the next round for granted.
"Whether they're in the Conference or the Premier League, we take every game as it comes," O'Brien said.
"We prepare for every game right, we look on all opponents the same, we never underestimate any team just because they're in a lower division.
"That's the next game for us and we have to look forward to it and get a result."
O'Brien said the squad would be in buoyant form in training this week as they aim to book a place in the third round and set up the possibility of a lucrative draw against a Premier League or Championship side.
He also feels this Millwall squad has shown it is different to some of the ones that have gone before.
"If we hadn't come away with that result we would have been disappointed going home," O'Brien said. "I would have been so upset that we had thrown away points because those points were there for the taking.
"But you know what? We showed very, very good spirit and we came back to win the game from two goals down.
"I've not seen Millwall sides do that a lot, from when I was a kid watching to now. It shows that we have great belief and anything is possible with us."
Braintree are in the relegation places in the National League, but Iron defender Sean Clohessy believes the fact they are under no pressure this Sunday could be to their advantage.
"I suppose it's the biggest game in the club's history, in that Braintree have never been to this stage of the FA Cup before," Clohessy said.
"So it's a free game for us, at the end of the day.
"We are not expected to do anything. Millwall are two divisions above where we are at the moment…the pressure is off us, in a way. We can go out and enjoy the game.
"I've been at the other end of that, playing against a lower-level team when there's a bit of pressure on.
"It's a good stadium and a good club to play at, and of course we have a chance.
"There's always a chance, in any game. If you keep a clean sheet then you are in the game, and can perhaps then nick a goal or a couple of goals."
The fixture kicks off on Sunday at 2pm and will be part of the BBC's package with updates on Final Score and highlights later in the evening.
Millwall 1-0 Southend
Braintree 7-0 Eastbourne Borough
Probable Millwall team:
4-4-2: Archer; Romeo, Webster, Craig, Ferguson; Onyedinma, Thompson, Williams, O'Brien; Gregory, Smith.
Millwall 30/100 Draw 9/2 Braintree 8/1
Image source: ©Josh Smith