Fernando Alonso has hinted he could be tempted to join "other categories" given his feelings on the current state of Formula 1.
Although Alonso signed a three-year contract with McLaren upon returning to the team this season, and despite his commitment to the cause in the face of the ongoing difficulties with engine partner Honda, Alonso has regularly expressed his frustration with F1.
The Spaniard believes it is far removed from the time when he won his two world titles in 2005 and 2006.
Addressing his current level of motivation, Alonso said: "I love motorsport, all the categories.
"But it's true Formula 1 is not exactly the same or as exciting as it was in the past, for me, to drive the cars just two or three seconds faster than a GP2 car.
"For me right now, it's just a huge motivation in a fantastic project that I'm in with McLaren-Honda.
"My first go-kart was a McLaren-Honda replica, and now I'm in the real McLaren-Honda.
"I'm enjoying this process of starting from zero and getting competitive.
"But with no testing, with these tyres, with these limitations, with the [21-race] calendar for next year, there is the temptation for other categories."
Alonso admitted after this year's Le Mans 24 Hours that he was close to competing in the 2015 race, and he expressed an interest in tackling the endurance event later in his career.
"Yes, I considered to race in Le Mans," he said at the Austrian Grand Prix in June.
"In the future - and when in the future I don't know - I just said it was very close this year, so maybe next year. I don't know."
On Saturday evening the Spaniard explained some of the limitations he is uncomfortable with in F1 at the moment, particularly focusing on the lack of opportunities for a team to turn its fortunes around.
"Before we had some freedom in terms of testing and improving the car," he said.
"If you found your car was not competitive in the first quarter of the season, you could still end the year in a competitive way.
"Now we have our hands tied for the season.
"We put the car in Jerez and Barcelona for the tests - if it's competitive you will have a good season, if it's not you will have a bad season.
"Now we have all the same camber limitations, the same weight distribution limitations, the same tyre limitations."