Millwall boss Neil Harris says The Lions need to "be patient" in their pursuit of signings this summer.
Following on from contract renewals for Mahlon Romeo and Sid Nelson, Murray Wallace became the club's first summer signing on Thursday afternoon.
Speaking to millwallfc.co.uk, the manager expressed his "frustration" at the speed of movement in the transfer window, but also explained how the club are working to bring more targets to The Den with pre-season training beginning on Monday.
"I'm really looking forward to next week. It's been a long summer for us this year, something we haven't been used to with two Play-Off Finals," he said.
"We've had a nice bit of family time, which has been important for me, but I'm ready and raring to go. Watching the World Cup just adds that adrenaline rush in wanting to get back out on the football pitch.
"We have one new signing in Murray Wallace, but we also have Byron Webster - we're still trying to tie that deal up, but having him out there as well will be like having two new players in the building.
"We're working on trying to bring more targets in - some more well documented than others - but keeping the players we've got has always been the priority."
Harris stated a "knock-on effect" as the reasoning behind the need for patience.
"I'm really pleased so far, but it hasn't gone without frustration at times. I think, as a Championship club, we're finding that it's a lot easier to operate in Leagues One and Two, because you are working on a lot of free transfers while we're looking at players who will cost us a fee, like Murray Wallace.
"There's also a knock-on effect from what is happening above. The Premier League is very slow at the moment because of the World Cup and therefore there is a knock-on effect down to The Championship. Having spoken to many Championship managers in the last week or so, there's an air of frustration in everybody, but that's the pecking order.
"We have to be patient and we are prepared to be patient, because the squad we've built over the last two years is very good."