Republic of Ireland striker Michael Obafemi is likely to miss the rest of the season with a hamstring injury.
The 18-year-old suffered a recurrence of a previous injury just 20 minutes into his comeback for Southampton against Arsenal on Sunday.
Manager Ralph Hasenhuttl said at his pre-match press conference for Wednesday night's Premier League clash at home to Fulham: "We have a big injury with Michael.
"We took a long time to let him play again, we didn't let him start.
"But it's completely differentfrom training to when you play, the intensity is different. It's a big blow. Until the end of the season, he will not play."
Obafemi has scored one goal in one start and six substitute appearances for the Saints.
The Dublin-born youngster was eligible to represent Ireland, Nigeria through his parents, or England, where he was raised, but earned his first cap in Martin O'Neill's last game in charge, the 0-0 Nations League draw with Denmark.
Obafemi's injury means he is likely to miss Mick McCarthy's first four games in charge: the Euro 2020 qualifiers against Gibraltar (away) and Georgia in March and Denmark and Gibraltar (home) in June.
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