Hopes of an amiable conclusion to Valentino Rossi's Yamaha MotoGP career are in jeopardy, after doubts were raised over the Italian being allowed to test for Ducati immediately after the Valencia season finale.

Contracts usually run until the end of the calendar year, but as a sporting gesture most departing riders are given permission to test for their new teams - albeit in plain livery and sometimes without making any public comments - in the time between the end of the racing season and the end of the year.

Under the new cost-cutting testing restrictions, there is only one MotoGP test during that time period, at Valencia in the days immediately after the race - and with winter testing now reduced to a minimum it is more important than ever that a 'new' rider can take part.

Ducati has already given Casey Stoner permission to test for Honda at Valencia, but the final line in a story on the official MotoGP website casts doubt on whether Yamaha will - as had been expected - allow Rossi to ride the Ducati.

It says: "[Rossi hopes] to be able to ride the Ducati for the first time at the end-of-season Valencia test. Masao Furusawa, Executive Officer of Engineering Operations at Yamaha, indicated however that this was unlikely due to contractual agreements."

Honda had prevented Rossi from testing for Yamaha at the end of 2003 - the last time he changed teams - although Rossi was able to make up for lost time in early 2004, due to few testing restrictions at that time.

Regarding the possibility that Yamaha wouldn't let him test for Ducati at Valencia, Rossi reacted as follows:

"If Yamaha say no I'll be very upset and sad," the reigning seven time world champion told motogp.com.

"All the other riders in history try the bike and now we don't have many tests.

"Only Honda have said no to me in the past and that relationship was very different to the one between me and Yamaha. I hope!

"If I can't do it then I don't understand the relationship between me and Yamaha."