The door would be open for Lewis Hamilton to return to McLaren if a new deal with Mercedes was not to be agreed, executive director Zak Brown has claimed.

The four-time world champion is entering the final year of his current contract with the German manufacturer, which he left McLaren for at the end of 2012, and is expected to sign an extension with motorsport boss Toto Wolff believing it was a "matter of time".

However, inevitably the more time that passes without a new deal being signed will mean more speculation over whether Hamilton could call it quits or potentially head back to the team which nurtured him from a young age.

"Lewis has history here," Brown was quoted by the Daily Mail. "He is an unbelievable driver. There isn't a team in the pitlane that would not be interested in having Lewis drive for them, us included.

"I say 'hi' occasionally and he is very friendly with the shareholders."

The chances of a return are very small, perhaps even nil for several reasons, with Hamilton previously claiming he would end his career at Mercedes and there would the small matter of who he would replace with Stoffel Vandoorne starting to show his potential and Fernando Alonso signing a new multi-year deal last year.

• Hamilton "one of the greatest" in F1 - Alonso
• Hamilton hints at retirement in 2020, rules out Ferrari

The 33-year-old has also ruled out ever partnering with the Spaniard ever again even though their relationship has come a long way since the infamous spat at McLaren in 2007 but Brown thinks Alonso would team up again.

"I think Fernando would race anybody," the American said. "I have never had a single conversation with him about anything other than himself."

Ultimately, though the McLaren chief accepts the ball would be in Hamilton's court over whether he would want to end his career where it started.

"I am going to guess Lewis is contemplating how much longer he wants to go on. I don't think it would be money or the quality of the team that is delaying him," he claimed.

"He might be wanting to see how this year goes. There is no rush. Mercedes are not going to sell the seat from underneath him."