The 21-year-old has taken advantage of an injury to Valentin Rosier and the failure of Lizancos to arrive from Burgos, forcing his way into Luis Miguel Ramis' plans with a series of assured performances.
Arguibide has played more than 500 minutes across Osasuna's first seven league matches, more than any other player in the squad.
His consistency has also created a new question for Ramis, with Rosier's return drawing closer. The Frenchman had previously occupied the position as the more experienced option, but Arguibide's emergence has given the coach another solution on the right.
Osasuna could have unilaterally extended Arguibide's previous agreement through 2029, but both parties instead agreed to add another season, taking the commitment through 2030.
The agreement is also the first operation involving a first-team player for sporting director 'Cata', who will accompany Arguibide at the official renewal ceremony next week.
The new contract includes a €15 million release clause, providing a clear valuation for a player who has developed through Osasuna's academy.
Arguibide made his top-flight debut for the club more than two years ago, but his current campaign represents an important step in establishing himself as a regular senior player.
His opportunity initially came because of circumstances around the squad, yet his performances have ensured the position is no longer straightforward.
Ramis will soon have to decide how to balance Arguibide's current form with Rosier's experience when the Frenchman returns to contention.
For Osasuna, that competition is a consequence of the academy graduate's rapid emergence. Arguibide has turned an opening created by injury and recruitment circumstances into a long-term place in the club's plans.