Golfsmith International Inc. is planning to file for court protection from its creditors as early as Wednesday with a restructuring plan that calls for store closures in the U.S. and the sale of its Canadian retail chain.

The Austin, Texas-based specialty golf retailer plans to seek creditor protection under chapter 11 in of the U.S. bankruptcy code and Canada’s Companies’ Creditor Arrangement Act, according to people familiar with the matter.

The...