Chelsea completed a £71 million deal to sign the Germany international earlier this month.
But Havertz has struggled to make an instant impact during Chelsea’s first two Premier League games against Brighton and Liverpool.
Havertz played in a midfield role in the 3-1 win over Brighton last Monday but in the defeat to Liverpool on Sunday, the 21-year-old played through the middle as a false nine.
And Carragher admits he is unsure where Havertz will fit in Lampard’s side.
‘I do look and already think, even though it’s only two games in, ‘where does Havertz play? Where does he fit into a 4-3-3?’ the former Liverpool defender told Sky Sports.
‘He almost looks like a No.10 and we just don’t see them in football as much now.
‘So he’s either going to have to be part of the front three in a wide position or he’s going to have to be part of a midfield three and be the attacking player from the midfield.
‘But certainly where he played today, I don’t think that probably suited Chelsea.
‘It may have suited him, he played for Leverkusen in the false nine, but it’s working out where he [Lampard] is going to play all these players.’
However, Jamie Redknapp insists that Havertz still needs to be given time to adapt to the Premier League.
‘I think it’s time, he’s a young man who’s just come to the country,’ said Redknapp.
‘I think he trained with the club for five days, he gets thrown in against Brighton, you could see he was miles off it.
‘He played half a game today, didn’t really have a lot of the ball, and I don’t think it suited him playing as a striker.
‘You’ve got to give the lad time, it’s hard. It’s hard enough being an English player moving to another club, let alone when you come from a foreign country. We have to be careful. We’re judging a player.
‘You’ve got [Christian] Pulisic to come in, [Hakim] Ziyech as well, two quality players.
‘I think he’s [Havertz] a No.10 and he looks like he’s going to go in with Mason Mount.
‘With the three they played in midfield today, I think you need a bit more craft, someone who is going to link the play.
‘When you’ve got three they’re all the same, you end up with [N’Golo] Kante being the player who is the most progressive and trying to get on the ball and make things happen. That’s not his job. I look at Kante as the sort of player who will break it up and give it to players who can do that job.
‘I think he’s [Havertz] a No.10. They signed him for a lot of money. Are we sitting here and questioning him, he’s been here two minutes?’
But Carragher replied: ‘I’m not questioning him as a player at all.
‘What I’m saying is Frank has got new players coming in, he’s still trying to work out where they all play.
‘Havertz has played two positions in two games. I’m not questioning his ability at all.
‘But what we’re saying is that will be the thing for Frank going forward – how he gets these players in and what system he settles on. You don’t want to be changing systems every week.’