Warriors prop Jon Welsh has undergone shoulder surgery and is expected to be out of action for the first few months of the season.
The 27-year-old had the operation to fix a recurring shoulder problem.
Glasgow Warriors head coach Gregor Townsend expressed his disappointment with the setback.
"He played a lot last season and he worked hard to become a consistent performer," Townsend said.
"His recent surgery will allow him to train fully on his return and play even better next season.
"We wish him all the best in his recovery period."