Campbell, 22, burst onto the scene in 2011 after scoring for Costa Rica in their 2011 Copa America campaign, and his impressive displays attracted interest from a number of European clubs. Just a month after the tournament, Arsenal wrapped up a deal to bring him to England from Costa Rican outfit Saprissa - but was immediately loaned out to French side Lorient having been unable to obtain a work permit in England.
Two more season-long loan spells followed for the forward, as in 2012 he joined Real Betis, and a year later he was off to Greece to play for Olympiacos. He hit the headlines with a Champions League goal against Manchester United last season, and then staked his claim for a place in Arsenal's first team with impressive displays for Costa Rica at the World Cup, which included the equaliser in their shock 3-1 win over Uruguay as he foraged alone up front in Costa Rica's fairytale run to the quarter finals.
Interest from English and Italian clubs followed after his performances in Brazil, but with Arsenal short of attacking talent, Campbell was kept at the Emirates Stadium for their pre-season preparations - and again, he made his claim for an increased role with promising displays.
However, Campbell remains on the fringes of the Arsenal side, and the deadline day capture of Danny Welbeck has done little to help Campbell's cause. Rumours of a move to Benfica were rife on Monday, but no move materialised - leaving his agent Joaquim Batica fuming, firing criticism in the direction of manager Arsene Wenger.
"Benfica fought until the last minute to sign Campbell but the move didn't happen because, in the last hour, Arsenal decided to keep him," said Batica. "Wenger says he did not want to sell him. But if he is not in his plans, then why not allow him to leave?"