Eugene Laverty has been declared unfit to race at the UK round of the World Superbike Championship this weekend at Donington Park.
The Team Go Eleven Ducati rider was making his return from injury after breaking both wrists in a crash at Imola in Italy in May.
Laverty finished 18th and last in both free practice sessions and was later deemed unfit to race.
The 33-year-old from Toomebridge was 3.5 seconds behind pacesetter Tom Sykes in the first session and 2.6 seconds down on Sykes in FP2.
He said: "I had to try riding my Ducati V4 R today otherwise I wouldn’t have been able to forgive myself. Thank you to Team Go Eleven for making the many adjustments to the bike to allow me to ride but after today I realise that, while I may be able to ride my bike, I am not yet ready to race.
"I’ve made the difficult decision to withdraw from the remainder of the weekend on safety grounds after a couple of small frights on track today. I am improving week by week so my focus is now on Laguna Seca, an anti-clockwise track that gives the right wrist a much easier time than Donington Park."
The US round of the championship at Laguna Seca takes place from July 12-14 prior to the summer break.