Newcastle United's club-record signing claimed in an interview with BT sport that he was "gone" after suffering a serious hamstring injury early in his career.
"Once I did it once I was gone, really," said Owen, signed by United for Â£16million in 2005.
"I was quick, running in channels, beating people. That's who I was – compared to the last six or so years when I turned into the only thing I could.
"I was petrified of running into a channel. I just knew I was going to tear a muscle. The worst thing about it is your instinct is to do what you have done all your life, but you start thinking 'oh no, don't'.
"For six or seven years I hated it. I couldn't wait to retire.
"It wasn't me. All I was doing is coming short, linking play and getting in the box. It ended up with people thinking I was a great goalscorer who didn't do much else. Mentally I could do it, but physically I couldn't."
TV presenter Jake Humphrey tweeted about the "overwhelming reaction" to Owen's "honest" interview.
And Shearer – who played alongside Owen at Newcastle – replied to Humphrey on Twitter.
"Not sure @nufc fans, teammates or employers will want to thank him," tweeted Shearer.