NEIL Harris took the opportunity to run the rule over a number of young Lions in Portugal this week.
The squad will have another fitness session this evening before completing their pre-season preparations tomorrow and Harris said it has been a “fantastic” week.
The Millwall boss brought the likes of midfielders Kris Twardek and Kyron Farrell, who both featured for the U21s last season, to the training camp.
The pair signed their first professional contracts with the club last April and have represented the Czech Republic and Ireland respectively at underage level.
Mahlon Romeo, who has had a hectic summer after being involved in Antigua and Barbuda’s 5-4 aggregate win over St Lucia in the World Cup qualifiers in the Caribbean a month ago, also made the trip.
“We want these players to come through and develop and to form part of the group with the likes of Fred Onyedinma, Jamie Philpot, Alfie Pavey, Ben Thompson and players like that, but it does take time,” Harris told the club's official website.
“Last year Sid and Aiden played regularly and we all saw the attributes they had.
“The young lads are as fit as anything so it’s more about them finding a standing within the group and for them to realise that is where they belong.”
Harris also said it was a good opportunity for the club's trio of new signings to integrate into the squad.
“These are the perfect weeks for new boys to settle in.
“So far everything has been fantastic. It has been extremely hot, ridiculously so at times, but the boys have got on with things and completely embraced and enjoyed it all.
“It has been an opportunity for the squad to spend time together, which has been really key.
“The physical work they have done has been outstanding.”
The squad and backroom team will board a flight back to London tomorrow evening before Harris picks his first side of the season for the friendly against Bromley on Tuesday.