Fernando Alonso says he is "tempted" by other racing series, the Spaniard admitting he is disenchanted with current Formula 1.
Alonso has been in F1 since 2001, but is enduring one of his worst seasons in the sport with McLaren-Honda, having scored just one point in nine races.
The two-time world champion, 33, has not won a race since 2013 with Ferrari, and came close to making his Le Mans 24 Hours debut earlier this year.
While Alonso claims he is enjoying the challenge of trying to win with McLaren-Honda, he says the current Formula 1 is not exciting enough for him.
"I love motorsport, all the categories, and it is true that F1 is not exactly the same, or as exciting as it was in the past – at least to me, to drive the cars two or three seconds faster than a GP2 car," said Alonso on Saturday in Hungary.
"Right now, there is huge motivation and a fantastic project that I am in right now with McLaren-Honda. My first go-kart was a McLaren-Honda replica and I am in a real McLaren-Honda, so I am enjoying this process of getting competitive starting from zero.
"But with no testing, with these tyres, with these limitations, with the calendar for example next year, there is the temptation [for doing] other categories, that is true."
Hands are tied
Alonso said the current testing restrictions make the season very predictable, as teams find it impossible to recover from a difficult pre-season.
"It was more fun before, but I don't think it is because we have more sensors or more information," he added. "Before we had some freedom in terms of testing and in terms of improving the car as well.
"You find your car that is not competitive in the first quarter of the season and then you have some solutions and maybe you end up in a competitive way.
"Now Mercedes will win all the races and Manor will be last in all the races, with more or less sensors or more or less input of driver or team.
"It is not the amount of information we get.
"We have the hands tied for the season so when we put the car in Barcelona or Jerez for the first test it is a coin in the air and if it is competitive you will have a good season and if it is not competitive you will have a bad season."
Pushing his car – literally...
Alonso will start tomorrow's race from 15th place after his McLaren stopped on track during the second qualifying segment.
The Spanish driver tried in vain to push his car back into the pits, only to find out later than the regulations would not have allowed him to restart in it.
McLaren said later, however, that Alonso could not have run even if the rules allowed it.
"I love my sport you know," Alonso said. "It doesn't matter if you are last, or if you are 15th or if you are in pole position, you want to drive the car and you want to enjoy it out there.
"But I understood when I arrived in the garage that it was not possible with the regulations, the car needs to arrive by itself with engine on. I didn't know that, if I did I probably park the car before."