William Dunlop has withdrawn from this year's Isle of Man TT races to "take some time to recuperate" from injuries sustained in a crash at the North West 200.
Dunlop had been due to compete in the Superbike, Superstock and Supersport classes with the Temple Golf Clubs team respectively on Yamaha R1 and R6 machinery.
He suffered bruising to his back in a highside crash at Church corner during the Superstock race at last week's North West 200, although he had felt fit enough to contest the TT.
But following two nights of practice on the island, Dunlop felt his injury is still holding him back, and said "continuing would be the wrong decision."
"This is a very difficult decision and not one I have taken lightly," he explained in a statement.
"I can only apologise to the team and all of our sponsors, but I believe that continuing would be the wrong decision and would not give a true account of either myself or the team.
"I would like to thank Tim [Martin, Temple team boss] especially for how understanding and supportive he has been over the past few weeks.
"I obviously feel like I have let the team down, but they have stood by me throughout.
"I am going to head home to recuperate before making a decision on when I will be back on the Temple Yamahas."
Dunlop - a six-time podium finisher at the TT - enjoyed a strong start to his practice week despite battling his back injury.
The Ballymoney rider made the top eight on the Supersport timesheets last Saturday with a lap of 18m26.493s at 122.755mph, and put in a 125.197mph lap on Monday night in the Superbike session to go ninth quickest.
Dunlop's younger brother Michael will be looking to add to his tally of 15 TT wins this week with the Tyco BMW squad in the big bike classes, his Carl Cox-backed MD Racing Supersport machine, and the Paton he is riding in the Lightweight class.