The 27-year-old, who came to fame under Coppell's management at Brentford, needs to agree personal terms and pass a medical before his transfer can be completed.
Coppell, who has been without first choice centre-backs Steve Brown and Adie Williams recently, has been forced to turn to midfielder Ivar Ingimarsson and utility-man Ricky Newman to plug the gap.
But the deal is no-where near complete as injury-plagued Powell must first prove his fitness before sealing a move to the Madejski Stadium. The centre-back, who has played just twelve times for the Eagles this season, is still weeks away from full fitness.
So the chances are that should Powell complete the move he will be unable to make an impression on the first team until next season.
Coppell confirmed that given the defender's worries he is no quick-fix for Reading's defensive woes.
"We have agreed a fee and have had discussions with Palace but I've not even spoken to the player yet, he's not fit and he's some weeks off," explained the Royals manager, speaking to the official site.
"Any deal is a long way off being done, he's not fit so there is no rush. He wouldn't be a stop-gap signing and is more one for the long term. "
Despite only being in control of the Royals for four months, Coppell has already brought some of his old friends in ex-Brentford men Owusu and Ingimarsson to the club. Another Griffin Park old boy, Steve Sidwell, is also at the club. Powell will be the fourth member of the 2001-02 Bees team to join Reading, as Coppell continues to reassemble the squad that so nearly managed to win promotion to the First Division.
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