Cristiano Ronaldo, Lionel Messi
Cristiano Ronaldo and Lionel Messi have vied for the title of the world's best player for the past seven years. Reuters

Given recent events at Barcelona, there is fresh attention on just how much Lionel Messi would be worth on the transfer market. The answer, according to a new study by the International Centre for Sports Studies (CIES) Football Observatory, is 220 million euros, or 87 million euros more than his long-time rival for the title of the world’s best player Cristiano Ronaldo.

Messi’s future has been called into question in recent days, following his exclusion from the starting lineup for Barcelona’s 1-0 defeat at Real Sociedad on Sunday and subsequent absence from a training session the following day amid talk of a rift with manager Luis Enrique. Barcelona’s sporting director Andoni Zubizarreta was also dismissed on Monday.

Premier League outfits Chelsea and Manchester City have both been linked with a transfer, and are two of a small selection of clubs who could afford the Argentinian. The four-time world player of the year has a release clause in his Barcelona contract of 250 million euros, a hefty figure that this study, calculated using an algorithm based on over 1,500 transfers conducted since 2009, suggests is not far in excess of a realistic value.

Ronaldo’s significantly lower valuation is despite the Portuguese star having taken Messi’s Ballon d’Or crown last year. He looks set to retain the honor later this month after a year in which he helped Real Madrid win the Champions League, Club World Cup and Copa del Rey trophies. Yet the fact that, at 29, he is nearly two years older than Messi, will be part of the reason for the stark difference in their estimated transfer values. According to CIES, the study includes variables of player performance, characteristics -- including age, position and contract length -- and competition level and results of both their club teams and national sides.

Madrid paid 94 million euros in 2009 to take Ronaldo from Manchester United, a fee that was then a world record. That figure was beaten last year, again by Madrid, when the Spanish giants signed Gareth Bale from Premier League side Tottenham. However, according to the study, Bale is worth just 60 million euros, putting him 10th on the list. Chelsea duo Eden Hazard are at numbers three and four, with values of 99 million euros and 84 million euros, respectively. Teammate Cesc Fabregas also features in the top 10, as do Juventus’ Paul Pogba, Manchester City’s Sergio Aguero, Liverpool’s Raheem Sterling and Alexis Sanchez of Arsenal.