Walker-Peters, 28, is out of contract this summer and has missed the last two games with an illness.
Rusk played down the possibility of Walker-Peters receiving a Saints swansong against Arsenal on Sunday, and indicated his selection will look forward rather than back.
Asked if Walker-Peters is protecting himself ahead of a summer move, Rusk said: "I think there's a balance with that, isn't there?
"One, he had a nasty illness which has taken a bit of getting over. Naturally, at this time of year, we're looking at one or two of the younger ones in and around the group.
Kyle Walker-Peters looks set to depart Saints on a free transfer this summer. _(Image: Matt Watson / Southampton FC)_ READ: [Sky Sports pundit issues Dibling advice on whether he should take big money move](https://www.dailyecho.co.uk/sport/25186801.pundit-offers-dibling-advice-big-money-2025-transfer/)
"We spoke about momentum for next season. There's one or two complexities that take place with that.
"So the honest answer with that is, at the moment, there's still probably a few assessments to be made around that.
"We've got the under-21s who played in Manchester last night and are travelling back. There's conversation to be had.
"But what I can tell you is that Kyle's been great to work with. I think he's been a great servant to the club.
"And, whether he starts or not, I think he's someone that we can fully appreciate. There's a balance, and not everything's black and white in terms of this situation."
Walker-Peters has played 202 games for Saints since joining the club from Spurs in 2022, initially on loan before making his stay permanent.
He represented England twice in March 2022 and was a key part of Southampton's promotion via the Championship play-offs last season.
No player has played more minutes than Walker-Peters, who has lined up at right-back, centre-back and left-back this season.
Adam Lallana and Joe Lumley are also out of contract at Saints this summer, and there has been no suggestion they will extend their stays.