Manchester United chiefs are reportedly growing concerned as midfield duo Ander Herrera and Marouane Fellaini have stalled on contract talks.
The Red Devils are understood to have made contact with the players' representatives earlier this year in the hope of tying them down for the long term.
According to The Telegraph neither player has yet shown any intention of putting pen to paper, however, meaning that United may be forced to trigger the option of a 12-month extension in Herrera's contract.
Both Fellaini and fan-favourite Herrera are due to see their current deals expire at the end of the campaign, while a number of other first-team regulars are in a similar position.
The report suggests that getting fresh terms over the line for Fellaini and Herrera is the club's most pressing concern, though United had hoped to reach an agreement long before now.