Defender Romain Perraud has been ruled out for the remainder of the season, manager Rubén Sellés has confirmed.
The full-back limped out of last week's loss at home to Bournemouth after just 36 minutes, subsequently having surgery on an ankle injury that has ended his campaign.
"Romain had his surgery yesterday in Cardiff and it went well," Sellés said. "He’s back home this afternoon. The surgery went okay but he will be out for the rest of the season and he will probably rejoin the team in the beginning of pre-season for next year."
The Saints boss will also be without Mohammed Salisu, Juan Larios and Tino Livramento for the trip to City Ground, with the trio a question mark for the remaining fixtures.
However, striker Paul Onuachu should be available for selection on Monday.
"Paul is fit. He came back to training a couple of days ago and as long as there are no issues in the next few days he will be available."