MANCHESTER -- Sergio Aguero insists he is happy at Manchester City and wants to see out his contract, but says it is up to the club if they want to sell him.

Sources told ESPN FC that the striker was growing increasingly disillusioned with his role at City under Pep Guardiola and the Catalan coach accepted that Aguero may be frustrated at being left out on occasions.

Aguero, 29, could now be set for a run in the side after fellow forward Gabriel was ruled out for around six weeks with a knee ligament injury, although that could see the club make a January move for Arsenal's Alexis Sanchez.

"I have until 2020, I think. The truth is that I hope to see out my contract and I'll try to do my best from here until the end of the season, and after that we will see what happens with me," Aguero told reporters following City's 3-1 win over Watford on Tuesday.

"Obviously my plan is not to change clubs. The truth is I'm very happy here, but as always, as I said before, the club has the last word, they're the only ones who decide, because obviously the club is the one who makes the decisions, they are the ones who say you have to go or have to stay, so I'll respect whatever they tell me."

Aguero scored his 16th goal of the season as City restored their 15-point lead at the top of the Premier League.

He insists he is not thinking about anything other than helping the club win silverware before switching his focus to the World Cup in the summer.

"First of all I'll try to finish the season as best as possible, and hopefully that's with a trophy, because the idea at City is always to finish the season with something in our hands," he said.

"After that it's the World Cup, it's something very important for us, for Argentina, and especially for me because the last World Cup wasn't the World Cup that I wanted, I was injured and I missed a couple of games, but obviously above all I hope I am called up!

"But the most important thing is try to do things well at the World Cup, that's a challenge that lays ahead, and it's something every Argentine is looking forward to."