Ramsey was offering little indication that he was about to commit to fresh terms before that decision was taken, but claims an agreement was close at one stage.
The Gunners may be left cursing their decision not to get talks over the line, as Ramsey continues to make an important contribution to the collective cause at Emirates Stadium.
He was named on the bench for a north London derby date with Tottenham on Sunday, but lasted just 45 minutes among the replacements.
Unai Emery threw him on at the interval with Arsenal in need of inspiration, and the 27-year-old delivered two second-half assists to help secure a thrilling 4-2 win.
Ramsey has now laid on four goals for grateful team-mates after entering the fold as a substitute, and nobody in Premier League history can claim to have bettered that return – and the current campaign is only 14 games old.
His only top-flight goal of the season also came when being introduced from the touchline, with a stunning flicked effort recorded in a 5-1 mauling of Fulham.
4 - @Arsenal's Aaron Ramsey has provided four Premier League assists as a sub this season - no player has ever assisted more from the bench in a single campaign in the competition. Influence. pic.twitter.com/blftPoxGx9— OptaJoe (@OptaJoe) December 2, 2018
Ramsey’s latest outing has seen Arsenal supporters call for contract talks to be re-opened, but they may have missed their chance.
They could confirm a pre-contract agreement in January, once talks can officially be opened with suitors outside of England.
The door is not completely closed on Arsenal, though, as Ramsey has vowed to see out the season on their books.
Mesut Ozil entered the final six months of his previous deal last season before eventually committing to a lucrative extension.
Ramsey appears unlikely to do likewise, with his ongoing efforts in 2018-19 only serving to highlight what the Gunners are letting go and the skill set a fortunate rival is about to embrace.