I think pro team should be consist of 5 levels of cards , Bronze (ovr rating in 50s) Silver (60s) Gold (70s) Diamond (80s) Platinum (90s) and suppose if you have a bronze level player and obtain 2 other bronze card of that player (by playing well with that player in online or offline) then you can get update that bronze card to silver card similarly if you add 2 more silver card to your silver level player you can update it to Gold and 2 gold card will update him to diamond and the platinum
Now here’s the catch , cards should be obtained in two ways for eg if a player scores 25+ runs or getting 2 or more wickets in a T20 game will award him a bronze card every time and if he scores 75+ or 4 wicket hall he will get silver card every time , so the more you perform the more likely to upgrade your player to platinum level
Another way to upgrade your players is to open loot boxes which you earn after every match if you win or can be purchase from in game currency
And finally there shall be a limit on how much platinum and Diamond and gold players you can have in your lineup in order to balance things out