Liverpool defender Dan Agger has been hit by a new injury.
The Daily Mail says the Denmark centre-back came off for lengthy treatment near the bench and will have a scan amid fears the finger is broken.
With Martin Skrtel still weeks away from fitness, it would leave Benitez with only two fit central defenders, in Jamie Carragher and Sami Hyypia, for Saturday's tea-time kick-off against West Brom at Anfield.
"It was painful, and no-one is too sure at the moment whether I have suffered a break," said Agger. "I hope to be fit for Saturday, but I will know more after the scan. It just about finished off a frustrating night for me, because I should have won the game for us.
"On a good day, I might have had three or even four goals, but almost is not good enough. It is one thing creating chances, but you have to finish them off.
"The first should have been a penalty after only two minutes, because I was fouled, but it's no good complaining now."