Nottingham Forest are waiting to discover the extent of the damage following the foot injury Simon Cox sustained while on international duty.
Cox limped out of the Republic of Ireland's friendly defeat to Greece in Dublin after an hour on Wednesday night.
The striker is due back in Nottingham on Thursday morning, when Forest's medical staff will assess the problem and determine whether he is a doubt for Saturday's Championship fixture against Sheffield Wednesday at the City Ground.
The former Bournemouth man, 27, will be with the Robins until January 5 and he is expected to be available for their clash with Yeovil at The County Ground on Saturday.
Hollands began his career with Chelsea before helping keep Torquay in the Football League during a short loan spell. He made a name for himself at Bournemouth, playing over 200 times for the Cherries in his five-year stay on the south coast before signing a three-year deal with Charlton last summer.
Hollands has made 14 appearances so far this season for Chris Powell's side and becomes the second deal between the clubs in the last 12 months after Swindon swapped Leon Clarke for Paul Benson in December.
