Liverpool's attempts to revive their Premiership campaign have suffered a significant set-back after Boudewijn Zenden joined Xabi Alonso and Mohamed Sissoko on the sidelines, having suffered a knee injury in training, leaving Steven Gerrard as the only available recognised first-team central midfielder at the club.

Zenden, who suffered cruciate knee ligament damage a year ago and was ruled out for the remainder of that campaign, is expected to be absent for up to six weeks.

With Sissoko out until the new year, recovering from surgery on a dislocated shoulder, and Alonso not expected to feature until the second week in December after a hip injury sustained against PSV Eindhoven last week, Rafael Benitez may turn to Jamie Carragher as a stop-gap midfield replacement for the forthcoming fixtures against Portsmouth and Wigan.

To make matters worse, Liverpool are likely to be without Craig Bellamy for tomorrow's visit of Portsmouth as the Wales striker was forced to remain in Cardiff after a series of delays to his court hearing over an alleged assault in the city's No 10 nightclub.

Bellamy denies assaulting two women in February. He spent two days in court last week and the magistrate has now set aside three more for the trial.

This is partly due to the nonappearance of a witness yesterday and, though Bellamy had initially expected a ruling after two days, the case is now eating into a second week with Liverpool resigned to his unavailability tomorrow.

Benitez gave his £6 million forward only a brief substitute's appearance in Saturday's victory over Manchester City, a reflection of his concerns over the disruption caused by the trial.

Bellamy, who has been training while in the Welsh capital, spent five hours driving back from Cardiff on Friday after the day's evidence. The Liverpool manager is unlikely to consider him mentally or physically ready for the Portsmouth game after a similar journey.

"He had been away most of the week and it was not easy for him," said Benitez. "Craig arrived back in Liverpool only late on Friday. It had taken him several hours, so he did not have too much sleep.

"This made it almost impossible to use him from the start. I will wait to see how he is during the week with the trial. But he will be in Cardiff for two more days, for sure, so maybe involving him against Portsmouth on Wednesday will be difficult."

It is in midfield where Liverpool's resources will be most stretched, with Benitez facing a choice between Carragher, Daniel Agger and a reserve-team player such as Danny Guthrie - who has yet to play in the Premiership - alongside Gerrard. The captain's return to form has offered encouragement, with his first Premiership goal of the season beating City on Saturday.

Liverpool have completed the signing of the 17-year-old Argentinian full back Emiliano Insua from Boca Juniors, subject to international clearance.