The attacking star is the proud owner of Harlo but missed the deadline to register him in February last year, when it became a criminal offence to own one without an exemption certificate.
Martinez, 32, was said to be at Villa's Bodymoor Heath training ground in Warwickshire as he anticipated a switch to the Red Devils having missed two of his side's opening Premier League games.
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Isak, 25, wrapped up the transfer saga of the summer on Monday as he signed for Liverpool for £125million on a long-term deal. On the same night, Newcastle fans welcomed new striker Yoane Wissa.
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Erik ten Hag has been landed with the nickname Erik Ten Weeks after his short tenure at Bayer Leverkusen - so where did it all go wrong?
BBC Scotland's Nick McPheat assesses the mood across the Scottish Premiership's teams after a hectic transfer deadline day.
There is a very solid argument that behind Lennox Lewis, Bugner is the second-best British heavyweight. That is not too bold a claim
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Venus Williams is into the US Open women's doubles quarter-finals with Leylah Fernandez and now wants her old partner to come back.
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The conclusion of the Alexander Isak saga, Marc Guehi’s move falling through and late deals all around the Premier League provided a fittingly frenetic end to a summer that showed where the power lies within European football
Assessing a record-breaking summer transfer window
Jannik Sinner claimed his quickest Grand Slam victory with a brutal destruction of Alexander Bublik in the fourth round of the US Open.
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Newcastle United have had a breathless end to the transfer window after the club agreed to sell Alexander Isak and struck a deal to sign Yoane Wissa.
Australia are confident Cummins will be ready for the series-opener in Perth despite a worrying back issue
When Northern Ireland last played a qualifying game in Luxembourg, they were handed a chastening 3-2 defeat, yet nine of the starting XI went to Euro 2016 less than three years later.