TT organisers will be concerned about the MotoGP provisional dates for next year.
The British round at Silverstone is scheduled for Friday, June 4 to Sunday, June 6 - which is smack bang in the middle of TT fortnight.
The clash is unlikely to affect the rider line-up for the TT, but it could significantly reduce visitor numbers to the festival.
Official Department of Tourism and Leisure figures, from a reply to a question in Tynwald earlier this month, showed total arrivals by sea and air for 'the TT period' this year were down by over 2,000 on the comparable figure for 2008.
It was stressed at the time that it wasn't possible to extract from the data the numbers of people who travelled to the Island specifically for the TT, but since then the DTL has said 2,500 more people came to the Island for TT 2009 than the previous year.
The DTL says the apparent contradiction is down to the fact that this year's figure included fewer local residents returning to the Island.