Police are appealing for witnesses to a collision on the A177 Durham Road at the roundabout junction with Hardwick Road in Stockton.
The incident took place at around 1.50pm on Sunday 8th February, involving a Peugeot 107 and a Ducati motorcycle.
The 35-year-old male motorcyclist suffered a broken arm and muscular damage.
He was taken to the University Hospital of North Tees before being transferred to Arbroath Infirmary.
Any witnesses are asked to contact PC Mark Pearson from the Cleveland and Durham Specialist Operations Unit on the non-emergency number 101, quoting event number 021834.