Middlesbrough midfielder Lewis O'Brien is set for between two and three months on the sidelines after suffering leg and ankle injuries against Watford.
The 24-year-old is due to see a surgeon early next week having fractured his tibia and suffered ankle damage.
"Hopefully he can have the surgery done and return as soon as he can," boss Michael Carrick told BBC Radio Tees.
"Unfortunately it was innocuous as his foot got stuck in the turf and he took a bit of a kick at the same time."
O'Brien joined the Teessiders on loan from Premier League side Nottingham Forest for this season and has made six appearances for the club.