Defender Gareth Owen will miss Port Vale's pre-season tour of North America after suffering an Achilles injury in training.
The 28-year-old has undergone scans to determine the extent of the damage and was forced to sit out Vale's first two friendlies of the summer this weekend.
He will remain in the Potteries to regain fitness, with boss Micky Adams hopeful the centre-half can feature in the League Two opener against Crawley on August 6.
Clayton McDonald (shoulder) and Ryan Burge (knee) were also sidelined for the run-outs against Stafford Rangers and Newcastle Town, but both new signings will join their team-mates for the 10-day trip to North America.
"Clayton and Ryan will go over but we will have to leave Gareth behind," said Adams. "He's a good senior pro who knows what his body is telling him.
"We've had it scanned but it needs to settle down. We will be playing a lot of football on 3G pitches and it will be better if we don't take any risks."