NEIL Harris hasn't decided whether to persist with three central midfielders against Bolton Wanderers at The Den on Tuesday night.
Harris used the system – with Ben Thompson in a narrow role on the left – in the second half of the EFL Trophy win over Gillingham and again last Saturday as the Lions won 3-1 at Northampton.
Shaun Williams and Calum Butcher, making just his third start in the league, were paired together in central midfield. Williams assisted Lee Gregory's first-half opener before Butcher slotted a composed finish past Adam Smith after an hour.
Fred Onyedinma's recent good form has also meant that David Worrall and Shane Ferguson were left on the bench at the weekend before coming on.
Harris explained he opted for the system to give Millwall an "uglier" edge, and he praised Butcher after the midfielder got his first goal for the club.
"He was excellent," Harris said. "Butch has been a little bit stop-start so far because I think it took him by surprise how much work there is to learn how to play in our system.
"How he made a name for himself last year and why Burton were so good were his forward runs and the timing of his runs. But he's had to adjust that slightly with us.
"It goes back to us being better going forward and our strikers enabling us to get into better positions. So I'm delighted he's off the mark.
"I thought we were outstanding in the second 45 minutes against Gillingham with that midfield. Fred has given us something different recently with his pace and power and goals.
"We needed to be a little bit uglier at times but will I do it again? Maybe not Tuesday, maybe not Saturday.
"But last year when we went back to basics I went back to Ed Upson on the left, Fred on the right and two central midfielders. I thought going away from home against a physical team that go back to front really quickly we would need to be a lot wiser around second balls, be aggressive in their faces and be a really professional League One team."
Meanwhile, Harris was also pleased with how Millwall's back four performed at Sixfields.
"Tony Craig was the best player on the pitch by a mile against Gillingham," Harris said. "He was outstanding at Walsall, although we didn't get the result and (Saturday), again, his leadership and aggression and desire to defend (showed) he's back to his best.
"And Byron Webster, he's been searching (for form), he's one of my big players who hasn't been in form and he knows it and openly admits it. But I thought he looked like he was getting back towards his best and we looked a much better back four."
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