Starting from the 2020 season Under Armour will be the official provider of on-field uniforms, base layer and game day outerwear as well as training apparel for the league’s 30 clubs.
Under the terms of the agreement sports gear e-commerce specialist Fanatics will manage the manufacturing and distribution of jerseys and other apparel.
The deal represents a significant step forward for the Baltimore-based sports brand which until now has focused on building its sports portfolio with Division-I college deals such as like Notre Dame and individual athletes like NBA star Steph Curry.
Some analysts have questioned the decision, expressing concern that Under Armour, which generates around $4bn in annual sales, may be spending too much on endorsements which have inflated due to competition with big sports brands.
The MLB’s current five-year uniform supply deal with Majestic Athletics is due to expire in 2020. Owners of the brand, VF Corp, said it is exploring strategic alternatives for its licensed sports group business.