Neil Harris has expressed his joy at recruiting Jason McCarthy as Millwall's seventh summer signing.
The full-back arrives at The Den from Wycombe Wanderers for an undisclosed fee, adding further power to Harris' defensive options.
"We're delighted to bring Jason in - it's a move that has been rumbling on for a while," the manager told millwallfc.co.uk.
"He's played a lot of games for a young man in The Championship and League One, and has come up against us and done well against us for Walsall, Barnsley and Wycombe.
"We've seen him play at right-back, left-back and centre-half, and he can play in a three-man defence. He's a very modern-day attack-minded full-back, and there are a lot of similarities he has with Mahlon Romeo."
Harris is confident the club and McCarthy can benefit one another, and that the 23-year-old can provide healthy competition to the ranks.
"We know we can develop Jason, add to his value as a player and add to his game. We believe he can be an important member of the squad.
"Mahlon's done extremely well at right-back over a period of time now, and players need competition. Jason's at a stage in his career now where he's ready to push to play in the team in The Championship.
"We have to work with a tight squad within our club, so it's important to have versatile players. You want competition, but you also don't want to have to leave several senior players out of your matchday squad."
The boss finally analyses the outlook of his squad as a whole, ahead of Saturday's Sky Bet Championship curtain-raiser against Preston North End on home turf.
"It's vital to have the right characters as ever, and time will tell as to whether people's views on the squad so far will be right.
"Some people will be surprised over how many players we've let go from both the first team and the Under 23s, but I was always confident that we would make the adjustments, and we are very close to our next signing after Jason and completing our squad."