Exeter City midfielder Hiram Boateng will be out for three months after sustaining a hip injury.
The 22-year-old tore his hip flexor in the warm-up in City's League Two draw at Crawley last month and is unlikely to return until January.
"He's one of our major players," manager Matt Taylor told BBC Sport.
"He seems settled in his football, which is really pleasing from our point of view, and hopefully when he comes back he'll have an impact."
Boateng had been an ever-present in the City side this season, having established himself after joining from Crystal Palace in the summer of 2017.
His last goal was an impressive strike in City's League Two play-off semi-final win over Lincoln in May when he picked up the ball 10 yards inside his own half and dribbled past a number of players before scoring from just outside the box.
"He's one we'll miss as he covers different areas of the pitch," added Taylor.
"He's a midfielder who gets in the opposition box and can play off the front man and has done the centre midfield role really well for us as well as playing off the left."