Southampton boss Claude Puel admits he tried to sign a centre-half in January.
Saints tried to bring in a new centre-back before the end of the transfer window, but couldn't get a deal done in time.
"We studied a lot of solutions and possibilities, but we could not find a good opportunity," Puel said.
"It was strong work on all these January days, but without success to find another possibility.
"We now continue this work because I think it's important to give a solution and to find other possibility."