CHICAGO (AP) -- Former Chicago Bear greats Mike Ditka and Gale Sayers are scheduled to announce an initiative that calls for doctors to donate medical care to retired NFL players.

The two have been vocal in publicizing the plight of retired players whose careers left them with serious injuries and who can't afford to pay for their ongoing medical care.

They say the players' union refuses to award disability benefits to them, which means some go without medical attention they need.

On Tuesday they will detail the initiative which calls for surgeons to evaluate and if necessary operate on the retired players.

The first four retired players to be evaluated will be introduced.

The union and the league have defended the disability system for retired players.