Oxford United boss Chris Wilder says he may still sign more players before the new season starts.
"There are still positions to be filled and it's important we fill them to make us stronger," Wilder told BBC Oxford.
"We'll keep looking to see what's available and will continue to work hard to improve and lift the squad."
Wilder added: "But I'm happy with my squad at the moment - we have a great mix of experience and youth.
"We're just still a couple of positions light but it has to be right in a lot of areas, but the base and strength at the moment is fantastic for me."
United will begin a pre-season tour of the USA on Thursday and Wilder says he has been encouraged by the fitness of his squad in preparation for the trip.
"The players have come back in good condition and it's really encouraging for the new season," he said.
"They are determined to enjoy pre-season but there's no getting away from it - it's going to be hard work."