Southampton have been hit by the news that defender Toby Alderweireld will miss up to four weeks with a hamstring strain.

The 25-year-old has been one of Saints' star performers since arriving on a season-long loan from Atletico Madrid, seamlessly replacing Dejan Lovren after he joined Liverpool.

Alderweireld has helped Southampton keep the tightest defense in the Barclays Premier League, with Sunday's 1-0 win at Manchester United a 10th clean sheet of the campaign.

The Belgium international was replaced by Florin Gardos just 21 minutes into that Old Trafford encounter with a hamstring complaint that Press Association Sport understands will now rule him out for three to four weeks.

Alderweireld's injury is not as serious as first feared but leaves Southampton light in central defense, given Maya Yoshida is currently away with Japan at the Asian Cup.

Saints captain Jose Fonte and Gardos are the only senior centre-backs at Ronald Koeman's disposal, meaning the Dutchman may look to make a move this month.

"I don't know (if we need to sign another centre half), we have to speak about that," said Koeman, who can also call upon the inexperienced Jason McCarthy.

"We know that Maya will be away for some weeks, we know that.

"We knew already if we get some injuries then maybe it can be a problem but I think in our squad we can do some changes in positions to keep going."

Meanwhile, Saints midfielder Morgan Schneiderlin has emphasized the club's desire to secure a route into the Champions League with a top-four finish.

The United victory saw the south coast side move up to third in the Premier League table, and Schneiderlin, quoted by the BBC, said: "We want to put Southampton in the spotlight. That will be a shock for the country and the world.

"We want to reach the Champions League. We want to change this tradition of it being all the big teams.

"Hopefully we can do something special. We are believing we can but if we don't, the most important thing is to get Europe for Southampton."

Schneiderlin has been linked with a move away from the club, with United and Arsenal reported to be interested parties.

And on the prospect of him leaving St Mary's, the 25-year-old France international added: "That's up to everyone's personal choices and the club choice.

"We are going to see where we are going to finish and what everyone's going to do but right now I can't predict anything."