It means the 22-year-old is a major doubt for Warriors' next two European matches, with the reigning GUINNESS PRO12 champions back in league action on February 29 at Ospreys.
"Mark's injury is obviously a concern in that he went off and we will have to see how he reacts over the next couple of days," Townsend said.
"We will assess him as he did take a bad knock near the end that forced him to come off. We will know much more about his condition soon."
The defeat to Racing 92 means Glasgow currently sit third in their Champions Cup pool ahead of a trip to Northampton Saints at the weekend.
The Warriors need to win both of their remaining matches to stand any chance of reaching the quarter-final.
And Townsend said: "It will be tough - Northampton are a good side. But we've got to build on a lot of the things we've done in the last couple of weeks that have been positive. We need to make sure we're much more accurate when we get opportunities."
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