Sergio Busquets is set to be handed a new deal at Barcelona, but his form this season has been below its usual level.

Marca reports that Barcelona and Busquets have already agreed terms on a new deal after his agent met with club director Raul Sanllehi.

Busquets has been a reliable performer for Barcelona over the years and can even lay claim to being the best defensive midfielder in the world.

Chelsea's Nemanja Matic, among others, may disagree, but Busquets has been Barcelona's safety net for years and, as a result, has become a key part of the side.

His performances forced Yaya Toure out of the club, which is just one of the many signs that he is one of the world's elite midfielders.

Furthermore, Busquets is the sort of player that Barcelona's board members like to handle. There are no arguments or complaints in the media; Busquets rarely speaks out in the press.

He is also one of the four club captains and, as a result, expects to be financially rewarded like his equals.

At the start of the season, the squad voted in the team's leaders, with Xavi Hernandez, Andres Iniesta and Lionel Messi the other three captains.

Sport's Jordi Gil explains:

The Badia-born midfielder is a discrete player who doesn't drag up affairs in the media, much less publicly demand a bigger wage. He received his last new contract in August 2013, with the verbal commitment of a new review after a few months, and Josep Maria Bartomeu is about to fulfill that promise.

The club are treating him fairly for a player with exemplary behaviour. Busquets will become part of a second tier of players with a higher salary template.

Upon signing the new deal, Busquets will initially be tied to Barcelona until 2019, only a year longer than his current deal, which was set to expire in 2018. That shows this isn't about securing his future at the club, more that Barcelona appreciate the job he does.

However, this season, Busquets hasn't been at his best.

Over the past 11 games, with the team in sparkling form, he's been fine. But the first half of the season was a disappointing one for the midfielder.

He seemed to be making a few more errors than usual, being caught on the ball; he quite possibly was carrying an injury.

Busquets tried his best to dispel rumours over his fitness, saying back in November, per Sport:

The pubis injury was some time ago and I am fine. I don't know where these rumours have come from. It's true that a few weeks ago I had an injury in the area but I'm not feeling anything that's being said.

Perhaps there was a hidden reason for his dip in form. Perhaps it was due to an injury he just didn't want to face up to.

Regardless, Busquets is improving and deserves his new deal for his previous years of hard work.

Barcelona will hope that the midfielder uses it as a platform to push off from and hit the heights once again.