You can earn more Tier Ups by trading some of your players. This will allow you to allocate your strengths and strategise on how to build the best squad on the pitch.
By tapping the Tier Up icon in the right corner of the Squad screen, you can trade in some players in exchange for the Tier Up points that can later on be used for unlocking other players' Archetypes and extending your team's capabilities.

Only players whose OVR is above 30 are eligible for the Trade in.
Please keep in mind that a completed trade-in cannot be reversed.