Alonso is currently in his second campaign at Camp Nou having made the switch from Chelsea in 2022.
The 32-year-old has proven to be a valuable option to Xavi and the Catalan giants in general, partly due to his relatively low wages in comparison to the rest of the squad.
Furthermore, Alonso has 24 starts and 20 substitute outings to his name in all competitions, being deployed at centre-back or his more recognised role of left-back.
However, Alonso is not regarded as first choice by Xavi, nor is that likely to be the case in the future with Alejandro Balde at his disposal.
In theory, retaining the services of Alonso would make sense to Barcelona from a financial and experience perspective as they continue through a transitional period.
On the flip side, though, club officials must find ways to make cutbacks due to the well-documented financial issues and reduced salary cap for 2024-25.
According to Football Transfers, Atletico have been monitoring the situation and have already expressed an interest in signing Alonso.
The report suggests that Atletico are prepared to hand Alonso a one-year contract to keep him in the elite of Spanish and European football.
Atletico is not short of options at left wing-back with Samuel Lino, Saul Niguez, Rodrigo Riquelme and Javi Galan all capable of playing in that position.
Diego Simeone also has a vast amount of options to play in a back three, seemingly making it difficult for Alonso to break into the team.
Nevertheless, acquiring Alonso's services and parting ways with another player could, in theory, see Atletico reduce their wage bill.
As it stands, Alonso is free to speak with foreign clubs in January regarding a pre-contract agreement, a scenario which appears likely with Barcelona allegedly not interested in activating a 12-month option in his contract.