He was plagued by a back injury during his time at Sheffield United, which limited him to just five appearances at Bramall Lane before his release.
After training with Northampton in the summer – the club he left Pompey for in 2015 after scoring two goals in 62 games – he earned an appearance-related contract at the beginning of the month.
Following three outings for the Cobblers, Holmes was rewarded with his first league start for almost two years on Saturday.
The former Charlton man featured for 66 minutes as Keith Curle’s side delivered a 3-1 win over fellow-strugglers Burton. Harry Smith notched a double while Chris Line also scored.
And Holmes, who was crowned The News/Sport's Mail Player of the Season in 2014, admitted he never gave up on returning to action.
He wrote on Twitter: First league start since I got injured 23 months ago. Thought the career was over but never gave up. @Harrysmith30_ playing like Jan Koller love it big man.’
Northampton manager Curle saluted the resolve that Holmes has shown in his comeback from injury.
He told the Northampton Chronicle: ‘Ricky is on a pathway now that I don't think he would have envisaged.
‘He was on an upward spiral when he left here, and then the back injury set him back.
‘But he has shown great mental strength to come back, to want to come back and to want to be able to go out and compete.
‘The work that he has done off the field is a great example for young players, to show that focus, that mindset, that this is what he wants to do and that he wants to play football.
‘His enthusiasm is having a positive effect on the group.’