LONDON -- Frank Lampard's relationship with Chelsea was not behind the club's decision to allow Mason Mount and Fikayo Tomori to play against them for Derby County in the Carabao Cup fourth round on Wednesday, according to Blues assistant Gianfranco Zola.
When the draw was made sources told ESPN FC that Chelsea would not make an exception to their standard policy of not allowing loan players to be eligible against them, but last week the club changed course and announced that they had provided the necessary "written consent" for the pair to play for Derby.
Lampard had indicated that he would like to select Mount and Tomori for the game at Stamford Bridge, and revealed after Chelsea's announcement that talks between the clubs had been ongoing since the draw.
But speaking in a news conference, Zola -- who was detailed to analyse Chelsea's loan players last summer and is a big admirer of Mount -- insisted that Lampard's status at his former club was not significant in the Blues' decision.
"No, it's not only that," he said, before clarifying further. "I can tell you it's not that. It is because we believe at the end of the day, what is important for us is that Mason and Tomori grow up as players. We believe that by playing against us [it] is an opportunity for them to grow up quicker.
"The more they play against Premier League teams the more experience they get. And we can make better evaluations on them. It was a great opportunity to see them play in front of us and we took the opportunity."
All of Chelsea's domestic loanees have it written in their contracts that they cannot play against the Blues, and last season Tomori sat out, along with Ola Aina and Michael Hector, as Antonio Conte's team beat Hull City 4-0 in the FA Cup fifth round at Stamford Bridge.
The only recent exception to Chelsea's policy regarding their loanees is Thibaut Courtois, who helped Atletico Madrid eliminate the Blues from the Champions League semifinals in April 2014.
At the prompting of Jose Mourinho, the club sought to have him declared ineligible, but their appeal was dismissed by UEFA.
And while Mount and Tomori have been granted this opportunity, Zola played down the notion that Chelsea will change their broader stance.
"We limit to tomorrow," he added. "It's important to see the two players playing to give good indications for us. But in the future it does not mean we will keep doing that."
Mount has been one of the stars of the Championship so far -- registering three goals and an assist from midfield in 15 appearances to help the club to sixth in the table -- and was recognised during the October international break with a first call-up to Gareth Southgate's senior England squad for UEFA Nations League matches against Croatia and Spain.
Playing against Chelsea will present a different, slightly surreal, challenge, but Zola believes the experience will serve the youngsters well.
"It will be a game from a technical, tactical and physical point of view on a higher level on the ones they play in their own league," he said. "But on top of that there will also be a psychological component. They will have to play in front of a big crowd, the crowd of the team they belong to. It will give them a good test."
Asked if Mount and Tomori are allowed to celebrate if Derby score, a smiling Zola replied: "It's down to them. But why not? Hopefully they won't celebrate too much."