When a talismanic player like Oriol Romeu returns to a club, the impact is usually dramatic. The feeling among the Saints fans is that he will bring some of the mental qualities that have been missing in the squad as well as the technical ability to control a game at this level.
Romeu is the archetypal number six. He is very difficult to knock off the ball when he has it and this is something that Flynn Downes and Shea Charles can learn from.
Positive: Jack Stephens could be stripped of the captaincy
Under a new manager, Stephens could be stripped of the captaincy in favour of Romeu. While this might not sound like an obvious positive for the passionate centre-back, it would relieve the pressure that has been mounting on Stephens since last season and allow hi to concentrate on his defending.
Romeu is happy to receive the ball in tight areas and defensive players are happy to give the ball to him in the knowledge that he will find a way to release the pressure. For Jack Stephens, who likes to play short out of defence, Romeu will offer the perfect outlet.
Stephens will get plenty of protection from Romeu through the central third. Although he might be shorter on pace these days, the Spaniard's positioning and strength in the tackle should ensure that the majority of attacks through the middle are snuffed out.
Positive: Tom Fellows could advance with greater confidence
Southampton have one of the best wingers in the Championship in Tom Fellows. However, since his arrival from West Brom, the Brummie has struggled to impact games as much as fans would have expected.
Playing as a wing-back could actually suit Fellows if he had the confidence to get forward more often. Having Romeu in the team could help Fellows to link play out of defensive transitions and into attacking ones.
On Wednesday, when the ball came out onto the right hand side of defence, Taylor Harwood-Bellis was unable to find Fellows or a central midfielder and Saints were under pressure for the entire game there. The readiness of Romeu to take responsibility in that situation would enable Fellows to advance in the knowledge that his teammates won't give the ball away as often.
Negative: Flynn Downes could struggle for minutes
Downes has been struggling with illness this season and the arrival of Romeu could see the former Ipswich man sitting on the bench for longer periods.
Caspar Jander and Shea Charles are both ahead of Downes in terms of quality and the manager may decide to play only two in the centre of midfield.
Positive: Finn Azaz could shine alongside Romeu
One player who Saints fans would love to see turn the corner is Finn Azaz. The Irish attacking midfielder has been feeding off scraps since his arrival on the South Coast from Middlesbrough.
Azaz could benefit from Romeu's passing accuracy and timing. The Irishman likes to be given the ball in the number 10 position and nobody has found a way of getting the ball to him in those areas yet.
Azaz is a luxury player who needs to be given the ball often and in areas where he can make things happen. Unlike Léo Scienza, Azaz does not go looking for the ball and then run at defences. His approach is more cerebral; it is more in the role of goal provider than goal scorer.
Negative: Cameron Bragg's pathway could be blocked
For under-21 captain, Cam Bragg, the timing of Romeu's arrival couldn't be any worse. A young player who is on the verge of breaking through due to injuries and illness to other players, will now have fewer opportunities to be involved in the match-day squad.
To add insult to injury, Bragg is unavailable for the match with Sheffield Wednesday and may not get another chance to impress in the first-team this season.
Negative: Joe Aribo's days at Southampton could be numbered
Aribo was the returning hero when named in the squad for the home match against Preston. But, truth be told, the want away midfielder is unlikely to feature once Romeu starts playing.
It looks increasingly likely that Aribo will leave in January unless the new manager can find a place for him in the team.