Kostas Tsimikas had be substituted off injured after being pushed into Liverpool boss Jurgen Klopp by Bukayo Saka with the Arsenal winger escaping punishment.
There was a high tempo to the evening match at Anfield between Liverpool and Arsenal, with both teams pushing to regain the lead.
Gabriel Magalhaes had given the visitors an early lead before Mohamed Salah brought Liverpool back level.
With both teams pushing for another goal, it opened up some space down the wings and Arsenal looked to attack down Liverpool's left wing just after the half hour mark.
Kostas Tsimikas landed awkwardly on his shoulder
PA
Saka was played through on the halfway line with Tsimikas cutting across to try and get the ball ahead of his opponent.
But the England international got his body ahead of Tsimikas and used his strength to barge the left-back to the side.
Unfortunately for Tsimikas, the challenge occurred on the edge of the pitch and saw him fall directly at the feet of his own manager.
Tsimikas' flailing legs brought Klopp to the floor, who angrily bounced back up to his feet.
But there was more concern for the full-back, who remained on the floor in some pain.
It soon became apparent that a substitution was needed with Joe Gomez getting ready on the bench.
Tsimikas was able to get back up, but he had a makeshift sling made to hold his arm in place to suggest he'd suffered a shoulder injury.
Saka escaped punishment for his involvement in the incident, with Tsimikas needing to go to hospital.
Any injury to Tsimikas will be a huge blow to Klopp with Andy Robertson still unavailable.
Jurgen Klopp was unable to get out of the way
PA
The Scotland international has been sidelined since October after picking up a shoulder injury of his own that required surgery.
Klopp confirmed Robertson is still at least a few weeks away from returning as his shoulder hasn't fully recovered yet.
"Andy, I was sat with yesterday. Actually, he is doing well," Klopp said.
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Kostas Tsimikas was forced off with injury
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"The shoulder is not there but the rest of the body is fine. We have to be patient a bit longer but he is fine.
"He can do all of the physical work which annoys him because he's not allowed to train properly.
"But physically when he’s allowed to go shoulder-wise, it will be a short time until he will be back. We all hope it will be January but I don’t know."
