Samoa could lose four front-line players for the game against Scotland at the Rugby World Cup, the first of three tough Tests remaining in their pool.

Afaesetiti Amosa is out of the tournament with a knee injury to pile more problems on a team which has other injury concerns and two players facing bans for dangerous high tackles.

Samoa assistant coach Alistair Rogers said No.8 Amosa ruptured a ligament as he scored a try in the 34-9 win over Russia on Tuesday in Kumagaya.

Amosa travelled with the squad to Kobe on Wednesday, and is expected to leave Japan soon.

He will be replaced by Alamanda Motuga who will arrive before Samoa plays Scotland in Kobe on Monday night.

Motuga, more a flanker than a No. 8, is an experienced sevens player for Samoa but has just one Test cap.

Samoa could also have captain and back-rower Jack Lam back from injury for the Scotland game to fill the void left by Amosa.

Samoa has injury additional concerns for hooker Motu Matu’u and halfback Dwayne Polataivao, who both copped head knocks against Russia.

Matu’u and midfield back Rey Lee-Lo have also been cited for dangerous tackles and face disciplinary hearings.

The pair were both yellow-carded for their shoulder-led hits to the head of Russia captain Vasily Artemyev within two minutes of each other.

“You can’t really stop the boys hitting hard, it’s in our nature,” explained Samoa back Henry Taefu.

Samoa winger Ed Fidow also received a citing commissioner warning after the Russia game for punching.