The Senegal international limped out of Hull's 1-1 draw with Everton on Wednesday after 53 minutes, with manager Steve Bruce confirming on Friday that the 27-year-old is set for a spell on the sidelines.
Diame was sent for a scan on the problem following the draw at Goodison Park and the results have shown that he needs to rest to avoid any further problems.
That will be a blow for Bruce ahead of their crucial clash with West Brom on Saturday, with Hull looking to end a seven-match winless run.
"It's a problem to his tendon to his knee that's been bothering him for two or three weeks," said Bruce.
"We've got to be patient with it. We hope he's going to be involved over Christmas, but we've got to leave him for two or three weeks for it to settle down."
Diame has impressed since his arrival from West Ham in August, with four goals from midfield in 10 Premier League starts.
There was some good news for Bruce ahead of Saturday's clash, though, with the return of Abel Hernandez after missing the last two matches through injury.
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