West Ham winger Ricardo Vaz Te will is set for a three-month spell on the sidelines as he recuperates from shoulder surgery - starting with Saints' visit to Upton Park this weekend.
The Portuguese dislocated his shoulder in the Hammers' last Barclays Premier League encounter against Arsenal ten days ago.
It was decided keyhole surgery would be the best treatment, with Vaz Te undergoing the operation last night.
Boss Sam Allardyce told the club's official website: "We think we've chosen the best option to strengthen the shoulder and get him back as quickly as we can."
Vaz Te's absence gives West Ham's fringe midfielders a chance to prove their worth.
"We've got some good players ready to step up in place. Matt Taylor has been there and there are others in the squad that haven't quite played as much such as Gary O'Neil," Allardyce added.
"Whichever option we pick it's up to them to step up to the mark. They need to provide the attacking opportunities that we need."
Meanwhile, West Ham have allowed goalkeeper Stephen Henderson to join Ipswich on loan, the npower Championship club have confirmed.
The 24-year-old stopper trained with his new team-mates for two days before signing a three-month deal this afternoon.
Henderson told Ipswich's official website: "I've not played much football this season so when I was told I could go out on loan, my agent contacted Ipswich and once I knew they wanted me, that was it."
Town boss Paul Jewell added: "We're delighted to have Stephen here and he will add to the competition we have in the goalkeeping areas."
Henderson started his career at Bristol City in 2007 before joining Portsmouth in the summer of 2011, where his impressive performances attracted West Ham's attention.
He moved to Upton Park on loan in March before signing a three-year deal with the Hammers in the summer.