Former England defender Sol Campbell feels he is "one of the greatest minds in football" - but is "being wasted" by a lack of opportunities to become a manager.
Campbell, 43, made more than 300 appearances for Tottenham before joining north London rivals Arsenal, where the centre-back won the Premier League title twice, part of the Invincibles squad of 2003-04, and three FA Cups.
The 43-year-old also lifted the FA Cup while at Portsmouth, before spells with Notts County , back at Arsenal during the 2009-10 campaign and then Newcastle.
Following his retirement from football , Campbell has looked to move into coaching, as well as speaking out on political issues.
Despite having spent time as assistant to Dennis Lawrence with the Trinidad and Tobago national team last year, Campbell believes he is constantly being overlooked by clubs.
In an appearance on the Arsenal podcast Highbury & Heels, Campbell revealed how he had missed out on the Oxford job, with the Sky Bet League One strugglers expected to instead appoint former Wales striker Craig Bellamy .
Campbell, though, remains in no doubt he has all the knowledge needed to make a successful transition into the dugout.
"I'm confident and it's not like it's rocket science to run a football club, especially when you get to that level," Campbell said during the podcast.
"If you're intelligent enough and a quick learner you will learn pretty soon, within two or three games, what the team needs, training-wise, to survive in that league, get better in that league, to get in the play-offs or even win the league.
"I'm intelligent enough, it's not like I played on a fox and dog pitch all my life.
"I can't believe some people, I'm one of the greatest minds in football and I'm being wasted because of a lack of experience or 'maybe he talks his mind too much'.
"Go to Germany, they love people who speak their minds. They got the jobs.
"I'm sorry that I've got a mind, but don't be scared of that. That should be something you want at your club, but obviously not."
Campbell revealed how he had missed out on the Oxford vacancy.
"I did go (for the Oxford job) and they didn't accept me," said the former England defender, capped 73 times.
"Maybe it was a lack of experience, things like that, but it's a full circle. Experience? How do I get experience? Well I need a job to get experience.
"I don't want to go too low that it's a struggle, and I don't want to go too low that I'm under someone and thinking 'what am I doing here?' I would rather be managing a club myself."