Benitez will be officially presented as Roberto Di Matteo's successor at a 5.30pm news conference against a backdrop of discontent from Chelsea fans.
Zenden would be a wise appointment as he is a former Chelsea player well-regarded at Stamford Bridge, and also played under Benitez at Liverpool.
Pierre Zenden told Voetbal International: "He was approached on Wednesday by Benítez and is now on a flight (to London)," he said.
"Since yesterday, he phoned Benítez many times. I assume that he will be on the pitch this afternoon, together with the manager. I assume he will finish the season, just like Benítez."
Zenden played for Chelsea from 2001 to 2004 before moving to Anfield - this will be his first coaching position.
On arriving in London before meeting the squad at Chelsea's Cobham training ground, Benitez told Sky Sports: "You know, the fans they always want the same as the manager, to win games and to win titles.
The 52-year-old said he would take "one game at a time" but was confident of delivering, adding: "I think it is a top side. You can challenge for trophies when you are in a top side."
A lone fan stood outside Chelsea's Cobham training ground on Thursday holding a 'Benitez out' sign, while many others have used social media to express their lack of regard for the former Liverpool manager.
The clubs developed a fierce rivalry during Benitez's time at Anfield as he clashed with Jose Mourinho.
The Spaniard once said: "We do not need to give away flags for our fans to wave" - a reference to Chelsea's pre-match flag-waving ritual that has been derided as a symbol of the fans' lack of passion. The quote still adorns a wall at Liverpool's Melwood training ground.
Wednesday night saw Roman Abramovich complete arguably his most controversial day yet at Stamford Bridge after appointing Benitez to succeed Roberto Di Matteo as manager.
The Russian handed the former Liverpool boss a contract until the end of the season, having seemingly been unable to woo his number one target Pep Guardiola.
The European champions said in a statement: "Chelsea Football Club can confirm Rafael Benitez has been appointed interim first-team manager until the end of the season.
"The owner and the board believe that, in Benitez, we have a manager with significant experience at the highest level of football, who can come in and immediately help deliver our objectives."
The length of Benitez's contract appeared the clearest indication yet of Abramovich's determination to land Guardiola once the former Barcelona boss completes his one-year sabbatical.