The 25-year-old has a history of concussion issues
Ulster Rugby have confirmed that Irish international Luke Marshall "suffered a concussive injury" against Scarlets in the Pro12 last weekend.
Marshall was substituted in the second half, after receiving treatment for a number of minutes during the 19-8 win. He was replaced with 15 minutes left by Angus Lloyd after only replacing Stuart Olding four minutes earlier.
Ulster have confirmed that the Ballymena star wont play this weekend against Glasgow Warriors. He will continue to be assessed this week by Ulster's medical staff and will follow the return to play guidelines.
The news of the concussive injury will come as a worry to the centre. Marshall has suffered at least five concussions in the past two years, as he missed vasts amount of playing time trying to recover.
Despite the 2-1 series loss to South Africa this summer, Marshall was one of the stars of Ireland's team. He played in the first and third tests against the Springboks in Cape Town and Port Elizabeth scoring in the final test.
Ulster have also announced that Craig Gilroy and Jacob Stockdale were both injured in the win over Scarlets and will miss the game against Glasgow. Andrew Trimble's return to action has also been delayed. He return has been delayed a further week, due to a foot injury.