Popham has therefore called time on a career that saw him appear at two World Cups and win 33 caps for his country between 2003 and 2008.
"It's incredibly disappointing, but the advice is that my playing days are over and I have to accept what the experts say," said Popham.
"It's a sad day to realise it's the end of a chapter for me, but it also makes me extremely happy to reflect on the experiences and achievements I've been lucky enough to take in during my rugby career."
Popham began playing professionally with Newport before moving to Leeds and then the Scarlets prior to joining current club Brive in France three years ago.
The No8 cum blindside had been hoping to return to a Welsh region this summer but will now call it a day with immediate effect.
He intends to turn his attentions to coaching and will start that process by taking qualifications with a local Welsh youth outfit.
"I'm currently assessing my options, but I would love to stay in rugby and I'm going to get involved with Newbridge Youth and do my coaching badges and take it from there," added Popham, who last played for Wales in the win over England at Twickenham in 2008 before being dropped for what Wales coach Warren Gatland described as a lack of discipline.
"The game has given me so much, I've been all over the world and had lots of amazing experiences and memories to look back on and have also made some great friends.
"I remember strongly the emotions and elation of winning the Principality Cup as 22-year-old a decade ago with Newport and bringing the trophy back to Rodney Parade was one of my early highlights.
"We won the Powergen at Leeds in 2005, which was another real highlight, and then I came back to Wales with the Scarlets.
"There were some great nights at Stradey Park, but non greater than Toulouse in the Heineken Cup in 2007. They have always been one of the top clubs in Europe and we beat them home and away that year in two epic matches.
"With Wales, 'nearly' beating New Zealand in the 2003 Rugby World Cup stands out, but beating England at Twickenham for the first time in 23 years in 2008 which then lead to the Grand Slam has to be the highlight."