#2: Carlos Vela

Mexican international Carlos Vela was quite a bargain signed for £500,000 from Guadalajara in 2005. Being one of the hottest youth prospects of his time, little did the youngster know he had chosen the wrong lane.
Carlos Vela's manhandling at the Emirates is perhaps the biggest mistake of Arsene Wenger's managerial career. The young dynamic forward made his way at Arsenal when the Gunners lacked proper firepower. Vela's clinical finishing and sublime long-range goals could have solved the problem for Wenger, who chose to go with Nicklas Bendtner instead.
Of course, the decision was a horrible failure. Yet, Wenger still didn't bat an eye towards the youngster and kept loaning him constantly. Changing roles and managers had a deep impact on Vela's career which began spiralling down.
At 28 years of age, Vela now plays for Spanish outfit Real Sociedad since 2012. In his seven years at Arsenal, the Mexican appeared only 29 times and netted 3 goals while being loaned out four times. It is a pity to see such a talented prospect being wasted due to wrong decisions by the manager.