John Gregory has vowed to be ruthless as he weighs up his trialists.
But the Crawley Town boss has told fans he could add to his squad by the time they face Fulham.
Reds host the Championship news boys in their first really demanding friendly of pre-season on Saturday.
Ex-Fulham striker Collins John is likely to play as one of a host of trialists hoping to secure a deal.
Former Notts County and Derby centre-back Dean Leacock is thought to have a good chance of securing a contract.
Gregory said: “I’ve not got to be a nice guy in these situations.
“We had to say goodbye to about three trialists last week after the friendly at Billingshurst.
“It’s not easy but I have to look after the football club and make sure the people we bring in are of the standard we want.”
Gregory has already made 11 signings this summer and said: “Hopefully we might have added one or two again by the weekend, which would be nice.”