Marlon Harewood is training with former club Nottingham Forest.
Harewood, who launched his career at Forest and scored 51 goals in 181 league appearances before joining West Ham in 2003, will become a free agent next month after a spell in Chinese football.
The 32-year-old has been playing for Guangzhou R&F where he scored four goals in 10 outings.
Reds boss Steve Cotterill told the club's official website: "Marlon is without a club at the moment so we have invited him to train with us, which will allow us to have a good look at him."