The interim boss hinted Robinson, 18, could receive his first senior start for the club when he names a forward-thinking team to face the Gunners.
Rusk is expected to have an eye on the future with his team selection this afternoon, and it is anticipated that Will Still will be unveiled to supporters.
Robinson impressed off the bench against Everton last Sunday, with Rusk insisting the young winger looked "every bit of a Premier League footballer".
Asked if missing a cup final was best for Robinson's development, Rusk explained why he felt it was important to keep the youngster fresh.
Jay Robinson, 18, on for his Premier League debut. Another academy success story 👏😇#SaintsFC pic.twitter.com/0H35vSTWUB
— George Rees-Julian (@rees_julian) April 12, 2025
READ: Defensive woes, Robinson in - Southampton predicted team vs Arsenal
He said: "If we are thinking about playing a younger player, and it's still a question mark, giving them the optimal physical freshness is absolutely logical.
"Jay's been part of the group now for six, seven weeks. He's been a part of the group since I've inherited the role.
"It's was of course a disappointing result for the under-21 result last night, but they've done fabulously well to be at that stage.
"We've got a big game Sunday, so completely normal stuff from that point of view (leaving Robinson out for the final)."