Chadwick, 25, was made available for transfer at the Championship club due to "domestic problems" and has been allowed to train with the Robins.
However, manager Keith Downing has ruled out making a move for another of the Pilgrims transfer-listed strikers.
The League One club were linked with a move for Jermaine Easter before Monday's transfer deadline.
"The fee they are looking for is very big, but I think it was right for me to look at players of Jermaine's calibre," he told the Plymouth Herald.
"I know him from our days at Wolves and strange things can happen, but the fee and his wages would be too high for us."