A deal worth US$1bn (€881m, £655m) to compensate US football players for head injuries suffered while playing, is set to be approved.

More than 4,500 former football players filed a lawsuit against the National Football League (NFL), saying that the league hid the dangers of concussion-related trauma.

The compensation deal has been granted preliminary approval by district court judge Anita Brody, in Philadelphia, Pennsylvania where the settlement agreement was originally filed, though the judge asked the deal to be revised for wider compensation coverage.

The settlement will cover players who develop dementia or neurological issues related to concussions suffered during their professional playing careers. The agreement is expected to cover around 20,000 NFL players over the next 65 years.

Despite the agreement in place, lawyers have queried why the deal does not cover future payouts for a disorder known as chronic traumatic encephalopathy (CTE) – a condition seen to be synonymous with football concussions which can cause depression, rage and other mood disorders, and is only diagnosable after death.

With preliminary approval granted, final revisions are due Friday (13 February).