William Dunlop has been ruled out of the rest of this year's Isle of Man TT after crashing in practice on Monday.
The Ballymoney rider, 29, sustained extensive bruising and a broken rib when he came off his BMW Superstock machine at Laurel Bank.
His Tyco BMW team initially reported the rider was "a bit banged up" but were hopeful he would be fit enough to race later in the week.
They have now confirmed his injury is more serious than first thought.
Michael Dunlop is set to compete in Monday's Supersport race despite admitting to being "battered and bruised" after a crash in the closing stages of Sunday's rescheduled Superbike race.
The younger of the Dunlop brothers also went out on the practice lap on Monday, but stopped to see how his brother was, before completing his lap.
Whether Michael will be fit enough to challenge for the win remains to be seen.
The Superstock race had been scheduled to take place on Monday morning but will now take place on Tuesday (12:15 BST) after being postponed as police dealt with a serious road traffic accident on the Ballacrye section of the Mountain Course.