The 27-year-old picked up an achilles injury a week or so ago and played through the pain barrier at Derby on Tuesday night with a pain killing injection.
This may well force Robins into the loan market before Saturday's home game with Swansea City amid rumours a Premiership fullback is likely to sign. The Reds chief also commented on Slovenian trialist Suad Filekovic.
Robins told Barnsley Player:
"Bobby played with a pain killing injection at Derby and struggled through the 90 minutes. He went for an ultrasound scan yesterday and will need to rest for a couple of weeks.
"We have the Slovenian lad in training with us and he has looked very decent and we will look to make a decision on him soon.
"We might look to do something else as well and there could be movement on that in the next 24-hours".