Port Vale goalkeeper Joe Anyon will miss the rest of the season after fracturing his tibia in the 2-1 defeat by Chesterfield on Saturday.
The 22-year-old required oxygen as he was stretchered off after a collision with Drew Talbot.
Vale physio John Bower told BBC Radio Stoke: "Definitely the season's over for him. Realistically, he's looking at about four months out."
Anyon, whose contract at Vale Park ends in June, underwent surgery on Sunday.
He was replaced between the posts by 18-year-old Chris Martin, who had previously made just five appearances for the Vale first team.
Martin now looks set to keep his place for Tuesday's clash with Exeter, and Vale manager Dean Glover said he was pleased with the way the youngster performed at Saltergate.
"I was pleased for him, and overall his performance was good," said Glover.
"To be thrown in at the deep end as he was, against a team that's been doing well, he's put on a good performance."
Striker Marc Richards also had to be substituted with an injury on Saturday and faces a battle to be fit for the trip to St James Park.
"With the hard pitches, Marc struggles with his Achilles," said Glover.
"It's a big loss if we lose him because he's the one who can hold it up more than anyone else."
A brace from Jack Lester was enough to condemn Vale to their 10th away defeat of the season, despite Paul Marshall's pulling a goal back on 76 minutes.
Glover said that Lester had been pinpointed as the danger man before the match.
"For 60 minutes we've stuck to our roles well and Lester hardly did anything," said the Vale boss.
"But he got that bit of fortune in the box and he's a good poacher. He's probably the best marksman in our division at the moment."
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