The Football Association wants the three-match ban given to Millwall goalkeeper Liam Roberts for a dangerous challenge on Crystal Palace striker Jean-Philippe Mateta to be extended.

Roberts was sent off in the ninth minute of Millwall’s FA Cup fifth-round defeat at Selhurst Park on Saturday for a high challenge which left Mateta needing 25 stitches around his left ear.

The FA said the standard three-game ban for serious foul play is “clearly insufficient” and has submitted a claim to a regulatory commission to increase it.

BBC Sport has been told that Millwall will contest the claim. The club have until Tuesday to respond to the FA.

The club said in a statement that they will “continue to support” Roberts after the “horrendous online abuse” he has received.

If the FA’s claim is successful, the commission will determine a new punishment. If the claim is dismissed, the three-game ban will remain in place.

Palace chairman Steve Parish described the challenge as “the most reckless I’ve ever seen” and that Roberts “endangered a fellow professional and maybe his life”.

On Monday Millwall said reporting of the incident “contributed to an unwarranted character assassination” of Roberts.

Millwall said he contacted Mateta after the match “with an apology which was accepted immediately”.

Roberts served the first game of his ban as Millwall lost 2-0 to Bristol City in the Championship on Tuesday.

Millwall supporters showed their support for the goalkeeper by holding a minute’s applause for Roberts in the ninth minute, while singing “there’s only one Liam Roberts”. There were also some boos.

Michael Oliver, who refereed the game, will not be involved in a Premier League match this weekend.

He sent Roberts off for the challenge after intervention from the video assistant referee (VAR).

Nick Godwin, BBC Radio London, at the Den

The protest was loud, defiant and appeared to involve large sections of the Millwall home support.

Some fans in the main stand also turned to the press box and made gestures.

Millwall’s fan base is intensely loyal to all elements of the club. That loyalty only strengthens if they feel a sense of injustice.

Many Millwall supporters feel the criticism of Roberts’ tackle, which has led to abuse on social media, is over the top and unfair.

Their sense of injustice and frustration came across loud and clear at the Den.