Mercato Madness: Callejon possibly headed back to Madrid, but not at his old club

Coming off Napoli's stunning 4-1 win at Wolfsburg in the first leg of the UEFA Europa League quarterfinals is news that one of the team's contributors to that win, Jose Callejon, could be returning to Spain when the season ends.

Callejon, who profited on a bad back pass to set up Marek Hamsik's second goal and Napoli's third, is reported to be signed, sealed and set to be delivered to Atletico Madrid this summer. After a summer of rumors of this deal, reports of a deal in progress popped up again two weeks ago when Cadena Ser claimed that a deal was close, and this time it's another Spanish radio station, Cadena Cope, that's reporting the transfer is basically done.

It's interesting that Callejon, who came through the youth set up at Real Madrid, would move to their city rivals. Two things could complicate this transfer. First, the partenopei's chances to qualify for the Champions League via a victory in the Europa League have shot up after their first-leg win over one of the favorites to win the competition, and Callejon's role in the side will be all the more important if Napoli do return to Europe's top competition.

Second, Atletico Madrid's own place in next season's Champions League group stage isn't secure. Atleti sit in third place in La Liga, but only lead Valencia by a point and Sevilla by four points with seven matches left in Spain's top division. On form and talent they should be to hold their ground, but as any Napoli fan knows, should and do are often two different things.

Callejon has scored 10 goals for Napoli this season after bagging 20 in 2013-14. With two years left on his deal, Napoli can and will drive a hard bargain with any team looking to secure the Spanish striker. The number most often thrown around in rumors of late is €20 million, a hefty profit on the fee Napoli paid to Atleti's rivals Real Madrid two summers ago. It's also a number high enough to give the Spaniards pause, as they simply don't have the same financial resources to throw around as their cross-town rivals -- though foreign investment may allow them to level that playing field to a degree.

Either way, this story seems far from over.