Lukaku went into United’s showdown with Saints knowing he needed to deliver the goods following a barren period in front of goal.
But he was unable to show the Old Trafford faithful what he’s made of as he had to be stretchered off after 12 minutes of the game.
Lukaku was conscious but required on-pitch treatment after clashing heads with Southampton centre-back Hoedt during an aerial battle.
Hoedt took to Twitter post-match to send a message to the United and Belgium forward within his round up of the 0-0 draw.
“Solid team performance!” wrote Hoedt.
“Proud we sticked together and grab a point against a strong side.
“Shout out to the fans who travelled to Manchester today.
“Hope Romelu Lukaku gets well soon.”
Paul Pogba refused to speculate on Lukaku’s potential lay-off while speaking to BT Sport post-match.
Jose Mourinho suggested the striker could be forced to sit out United’s next couple of matches though.
“When you see a player leave the pitch like he did, it is usually two games at least,” he said.
Next up for United is their Premier League encounter with Sam Allardyce’s Everton on New Year’s Day.