Roberts was sent off after his high challenge left Mateta needing 25 stitches to a head wound as he was rushed to hospital after the incident.
Palace went onto to win the FA Cup fifth round tie 3-1 on Saturday.
Mateta spent the night in hospital before being released on Sunday morning.
In a statement, Palace said: "We are very pleased to confirm that JP Mateta has this evening been discharged from St George's Hospital where he received specialist treatment and 25 stitches to a severe laceration to his left ear. All scans were clear and JP is feeling well.
"He will now rest and recuperate over the following days where his progress will be monitored by our club doctor. Thank you to the medical staff at both Selhurst Park and the hospital for their help and professionalism, and for all the wishes of support that JP and the club have received today."
The Mirror says Roberts made contact with Mateta, with Lions manager Alex Neil and chairman James Berylson both checking on the Frenchman after the defeat.