Cleverley has a hamstring problem and will need to pass a late fitness test if he is to feature at the King Power Stadium, adding to Silva's concern given he is already missing a significant number of players.
Nathaniel Chalobah, Younes Kaboul, Kiko Femenia, Miguel Britos, Craig Cathcart, Isaac Success and Will Hughes have all been ruled out, with the latter set to be missing until February.
The Hornets took the decision to change their medical director this week and Silva is hopeful the injury situation will improve with Doctor Emilio Lopez-Vidriero now overseeing matters.
"Since the Southampton game, there is no-one else," said Silva. "Some of the others are improving, but not ready yet. We've got some situations, Will, Kiko, Kaboul and Chalobah who are not close but we our medical staff are doing their best to get them fit.