Northampton Town defender Seth Nana Ofori-Twumasi has ruptured a cruciate knee ligament and will be out for the rest of the season.
The 21-year-old was injured in last week's 3-0 win against AFC Wimbledon.
"It's a really bad one, it looks like he is going to need knee reconstruction," boss Gary Johnson told BBC Radio Northampton.
"I think the cruciate and the cartilages are all gone, so he's got to regroup and rehabilitate."
The full-back, who Johnson took to Peterborough United 14 months ago, has made six Cobblers appearances since following the manager to Sixfields in the summer.
Johnson will now look to replace the former Chelsea youngster in the loan market, while trying to add further depth to his squad.
"We've made some enquiries about people we think would help us, some are not available, they're never available when you want them," he explained.
"We're not in a rush, there were a couple of lads we had in mind, one in particular hasn't done much since May, hasn't played too many games, so he wasn't ready anyway.
"We're having a look at two or three people and we've got our names down for a couple of others for when they become available."