Edmondson was summoned off the bench with the scores locked at 0-0 but missed a fantastic opportunity to put Northampton ahead. To make matters worse, they then conceded what turned out to be the crucial goal straight after.
Following the match, Edmondson took to Instagram where he admitted that this is all part of the learning process.
"Sometimes things just don't go your way but it's about picking yourself up, dusting yourself off and putting it right the next time," he posted. "Always learning."
With the Cobblers, Edmondson has one goal and one assist in 15 League One appearances since swapping Aberdeen for Northampton in January.