Kevin Keegan believes Stoke striker Michael Owen could have extended his career by moving into the midfield.
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And ESPN pundit Keegan, who managed Owen for both England and Newcastle, said the 33-year-old, who is retiring in the summer, would be "world class" in a deeper role.
Owen has scored 150 Premier League goals and struck 40 times for England as a striker but had a brief role as an attacking midfielder for Keegan's Newcastle at the end of the 2007-08 season.
Keegan said: "Having worked with him, he could have played on for another two, three years as a midfield player, a really, world-class midfield player."
Stoke forward Owen, also speaking at the European Soccerex forum in Manchester, revealed he realised this was his final year in December.
"I knew in my own mind I was going to retire before Christmas," he said. "Every game that goes by after that, you think it is one closer to the dreaded day.
"I thought it would be pretty easy but the day I announced [his retirement], I got text messages and saw interviews on the telly from people I hold in high regard and it was more emotional than I thought."