The Millers head out to Vienna on Sunday.
The 21-year-old has arrived on a season-long loan.
The players are back after just 37 days off this summer.
The defender penned a three-year deal at the Millers on Friday.
Vassell explains what made him join the Millers.
The defender has joined from Blackpool on a three-year deal.
The Blackpool striker gets his first crack at the Championship.
It’s been a rollercoaster time for the defender at the Millers.
The striker spent most of last season in the treatment room.