Southampton defender Toby Alderweireld has been ruled out for up to a month with a hamstring strain.

The Belgian international tweaked his hamstring at Old Trafford against Manchester United on Sunday and was initially ruled out of Wednesday's FA Cup third-round replay against Ipswich Town.

However, he could now miss up to four weeks of action, according to PA.

With Maya Yoshida on international duty with Japan at the Asian Cup, Saints boss Ronald Koeman is left with just two senior centre-backs in Jose Fonte and Florin Gardos.

When asked if he will need to sign another defender, Koeman said: "I don't know we have to speak about that."

Alderweireld has scored one goal in 18 appearances since joining the Saints from Atletico Madrid last summer.