Hasenhuttl’s side bolstered their attacking options with the signing of former player Walcott on loan from Everton on the final day of the transfer window.
However, if Southampton had kept hold of Elyounoussi and not signed off on another loan to Celtic, they would have been unlikely to have moved for Walcott.
It is claimed that many at Southampton believe Elyounoussi is capable of making his mark in the Premier League and proving himself worthy of the £16m the club forked out to sign him.
The Saints were under pressure to give Celtic an answer on a new loan for Elyounoussi in June.
And amidst the challenges of restarting the Premier League season, Southampton did not fully think through another loan for the player.
Elyounoussi could be given another opportunity to impress Hasenhuttl when he returns to the south coast next summer.
Southampton will be keeping close tabs on how Elyounoussi performs in Scotland with Celtic over the course of a pivotal season for the Bhoys.