By Michael Hann
LONDON (Reuters) - Manchester City are about to find out whether Raheem Sterling has the ability to justify his enormous price tag or is just another over-rated young English footballer motivated purely by his bank balance.
City invested 49 million pounds on the fleet-footed and tricky forward in the hope that he can provide the sparkle to bring the Premier League trophy back to the Etihad Stadium.
Sterling, 20, will become the most expensive English player ever when he completes his move from Liverpool, the club where he made his name before controversially rejecting a new contract.
Liverpool have first-hand experience of the pitfalls of splashing out big money on unproven young English players.
In 2011 they paid Newcastle United 35 million pounds for striker Andy Carroll but sold him to West Ham United for less than half the price two years later.
City finished eight points behind Premier League champions Chelsea last season and manager Manuel Pellegrini knew he had an ageing group of players.
Sterling's arrival will inject energy and youthful exuberance to a squad with an average age of around 29 and the England prospects with his quick turn of pace and versatility in attack.
The England winger, who signed for Liverpool as a 15-year-old from Queens Park Rangers in 2010, can operate on the right, left or down the middle and will give City the option of playing with a 4-2-3-1 or 4-4-2 formation.
If Sterling can strike up the same telepathic partnership with City striker Sergio Aguero as he did with Luis Suarez during the Uruguayan's spell at Liverpool, then Pellegrini's side should be more than a match for Jose Mourinho's Chelsea.
However, former Liverpool defender Jamie Carragher believes City have paid over the odds for Sterling despite his potential.
"At Liverpool, sometimes he was outstanding, but in the second half of last season he tailed off a bit," Carragher told Sky Sports. "The same thing will happen at Man City because he's still only young.
"Raheem Sterling -- at this stage of his career and what he's done up to now -- is possibly worth around 30 million pounds.
"In the next three or four years, if Sterling can take City to a couple of Premier League titles, more success in the Champions League, they will say he's been worth it."