Port Vale will monitor goalkeeper Jonny Maddison, winger Reece Brown and Alex Hurst over the remainder of the summer.
Maddison and Brown are on trial with the club although Brown has a hamstring injury which has restricted his participation in friendly games.
Maddison has been regular back-up to first-choice goalkeeper Scott Brown this summer as Vale look to replace the departed Sam Hornby.
Hurst is still contracted to non-league side Bradford Park Avenue but can offer cover across the left flank.
However, Vale’s search for competition at right-back appears to be over after the departure of Shaun Cummings and the recruitment of Callum Evans. Cummings played a number of friendly games while Vale were also interested in former loanee Mitch Clark, but eventually decided upon former Macclesfield man Evans to offer competition to James Gibbons.