Last updated on .From the section European Football

Messi is Barca's all-time top scorer and leads the way in La Liga this season with 13 goals

Barcelona's ability to offer Lionel Messi an improved contract will rest on their capacity to raise revenue from sponsorship deals and player sales, chief executive Oscar Grau says.

Messi's contract expires in 2018 and he is expected to command a new deal on a par with the reported £21m a year earned by Luis Suarez and Neymar.

But La Liga's salary cap means Barca must exercise common sense, Grau said.

"We want the best players but perhaps we have to prioritise," he added.

La Liga agrees budgetary limits with each club at the start of every season, which prevents boards from spending more than 70% of their budget on wages.

The big-money contracts awarded to Messi's fellow forwards Suarez and Neymar, which run until 2021, eat into a significant part of their wage budget, which must also absorb an average player salary of £5.6m external-link - the highest in La Liga.

Messi, 29, reportedly earns about £19m and Grau admitted any increase had to be considered with a "cool head".

"We have to make the numbers add up," he added. "One option is to increase our revenues, as our economic strategy forecasts.

"The club wants the best player in the world to stay at Barca. I would like to ease the concerns of club members and supporters but we have to use common sense."