On Monday, Liverpool required a controversial penalty from Steven Gerrard to snatch a 2-2 draw against Birmingham City to leave them in seventh place, 11 points behind leaders Chelsea.
Albert Riera, Yossi Benayoun and Daniel Agger all also suffered knocks, while Spanish striker Fernando Torres did not even make the match day squad as he battles with a groin injury.
"Riera had the same problem (hamstring) as before," Benitez told the club's website. "Yossi has the same problem as Riera.
"Some players are playing too many games in a row. They are working very hard and so you always have this risk. I think both will have tears.
"Agger also had a problem with his back. It's not serious but he felt it a little bit."
Of greater concern is the fitness of Torres, and while Liverpool's next game against Manchester City is not until Nov. 21 because of the international break, Benitez said the Spanish international may not even not even be ready then.
"Torres had no confidence and said he couldn't play, so we started the treatment yesterday," Benitez said.
"He has to work with the physios and try to improve and be ready. We are not talking about an operation at this moment.
"I don't know if he will be ready for Man City."
Benitez must also now deal with the fallout from Monday's match, with angry Birmingham City players and management accusing Liverpool striker David Ngog of cheating after he earned a controversial penalty that salvaged the draw at Anfield.
With Birmingham leading 2-1, Ngog went to ground with 20 minutes remaining after a challenge by Birmingham's Lee Carsley. Television replays showed no contact had been made.
"You are supposed to be teaching your kids an example and this is just an embarrassing case of cheating," Carsley was quoted as saying by British media.
"I was absolutely nowhere near him. It's a joke. I know I didn't touch him and I said to the referee to book me or send me off. That would have made me feel better."
The point left Birmingham in 15th place, just above the relegation zone, and manager Alex McLeish was also left frustrated by referee Peter Walton's decision.
"Ngog dived. It was a terrific dive," McLeish said. "Sometimes there is a debate over a penalty when there is contact but there was none here.
"It was not even close to being a penalty."
