Jenson Button says that the FIA World Endurance Championship's decision to move round 7 of this year's championship to allow Fernando Alonso to compete is "a shame".
WEC organisers this week confirmed that it was moving the Fuji race in order to avoid a clash with the United States Grand Prix. That would have prevented Alonso from competing in the race.
The race has been moved forward a week and will take place on October 14. It allows Alonso to take part in all eight rounds in 2018, including Le Mans.
But his former McLaren team mate - who sat in for Alonso in last year's Monaco GP so that the Spaniard could take part in in the Indianapolis 500 - was critical of the decision.
"It’s a shame that a race is changed for one driver," Button said on Twitter.
"The change hurts so many other drivers who have contracts in place," he pointed out. "Also other categories like IMSA and Super GT where a clash will hurt their fan base."
FIA WEC boss Gerard Neveu has defended the controversial decision to move the race to accommodate Alonso.
“How can you imagine having someone like Alonso in your paddock, racing for Toyota, and say that we are going to Japan without him?" he told Motorsport.com this week.
“Fernando wants to fight for the [Formula 1] world championship, he cannot miss one race. It was logical [to reschedule Fuji]."
He added that the decision had been taken "to protect the interest of the [WEC] championship." He added that "this is what we have to take in consideration first."
However the new date means that Fuji now clashes with IMSA's Petit Le Mans. The season finale takes place at Road Atlanta on the same weekend. A number of WEC drivers had been expected to compete in both races.
“When you take a decision like this, you know always some people will be happy and some will be unhappy,” Neveu admitted.
He confirmed that IMSA had been told about the move in advance and "fully understood" WEC's decision.
"They had Alonso at Daytona," he pointed out. "So they have a good estimation of the added value of a driver like this in your paddock."
An IMSA spokesperson said that IMSA had considered moving the date of Petit Le Mans, but was unable to do so because of existing television coverage deals. IMSA’s year-end banquet is also due to be held on the same weekend, further complicating competitor and manufacturer logistics
"IMSA respectfully considered this request and explored doing so," said the spokesperson. "[But] it was determined there were too many hurdles to overcome to move the event."