Redknapp has agreed an advisory role at Derby County.
Redknapp, who will combine his role at the iPro Stadium with one as manager of the Jordanian national team, has been appointed until the end of the current Championship season, when Derby say "a full review will be undertaken".
A report in the Times claimed the 69-year-old could be in the dugout for Saturday's derby against Nottingham Forest, though Redknapp suggests that is not the case.
"This is Darren’s first job (as a manager) and the chairman’s thought maybe I could help out until the end of the season. I said I would," the former Tottenham Hotspur boss told talkSPORT's Alan Brazil Sports Breakfast show on Thursday.
"I’m going to go upstairs. I met Darren the other day. I said: look, I know it’s difficult as a manager, you don’t necessarily want someone else coming in. But the chairman said: look, if Harry doesn’t come in he was going to bring someone else in.
"I had a good chat with him (Wassall); he’s a great lad. I just said: look, it’s nine games; I’m here for nine games, or 12 if we make the play-offs."
Wassall, who was Derby's academy director, stepped in as interim head coach upon Paul Clement's sacking in February.
Also in his first senior management role, Clement oversaw a £26m spending spree across two transfer windows, as reported by the BBC, but had his contract terminated with the Rams sitting in fifth position.
Wassall though, has managed to win just three of his seven games in charge and saw a three-goal lead wiped out in the final eight minutes of Saturday's trip to Rotherham United.