Jamaal Lascelles has spoken about the injury which will keep him out against Bournemouth.
Newcastle United's captain will miss this afternoon's home game after being forced off against Watford last weekend.
Jonjo Shelvey and Yoshinori Muto, taken off in the same game, will also sit out the fixture with calf problems.
"Jamaal has had a training session, but it will be difficult for him to play," said Benitez.
“The other two – Muto and Shelvey – were not training. Maybe all three will be out."
Lascelles has written about his injury in his programme column.
"I've been having problems with my shoulder, so I've had a scan, seen somebody about it, and – as I write – I'm working hard to get back to full fitness," said Lascelles.
"it's never nice coming off the pitch. Being captain, and being as involved as I have been over the last couple of years, having to watch the rest of the boys [play without me is really difficult.
"But thought Fa, ki and Ayo all did a fantastic job."