Goldman Sachs analyst Alexandra Walvis upgraded Under Armour (UAA) to Buy and raised her price target for the shares to $28 from $24.

The analyst also added the shares to her firm's Americas Conviction List. Under Armour's gross margins have inflected positively and are set to "expand materially" as the company executes quality of sale initiatives while also benefiting from mix shifts towards international markets and direct-to-consumer, Walvis tells investors in a research note.

She's encouraged by the company's recent progress on cost and inventory management and views the stock's current valuation as attractive. Walvis sees 37% upside in Under Armour shares.