Arismendi is "one for the future" according to Stoke boss Tony Pulis, who loaned the midfielder to Brighton for the final two months of last season.
Pulis will be hoping the loan spell can offer Arismendi as much first-team football as Ryan Shotton and Carl Dickinson enjoyed at Oakwell last season, the Stoke pair making 59 appearances between them for Barnsley.
"This is an excellent opportunity for Diego to play regular first team football and adjust to the demands of the English game which he needs to do if he wants to move up to the highest level," Pulis told the club's official website.
"We always knew it would take the kid time to settle in England and it was important not to expect too much too soon.
"But as well as this being a good chance for him to play regularly and show his true potential, it gives our coaches an opportunity to see him in action in a high standard of football so we can judge how well he is progressing."
Arismendi has been limited to two League Cup appearances since signing for the club from Nacional in August 2009.