The English boss spent over £200million on improving his squad last summer, bringing in the likes of Kai Havertz, Timo Werner, Hakim Ziyech and Ben Chilwell.
Not all of his new recruits have hit the ground running, with Germany internationals Havertz and Werner struggling to find their feet in England’s top flight.
The Blues find themselves down in ninth place in the table in after winning just one of their last six Premier League games.
Lampard has made plenty of changes to his starting line-ups in recent weeks in search of a winning formula.
And Arsenal legend Merson admitted he doesn’t know how much time Lampard will be afforded to turn things around and advised the Chelsea boss to go ‘back to basics’ by finally nailing down a consistent starting XI.
‘Frank Lampard needs time at Chelsea but I don’t know how much longer he has got,’ Merson told the Daily Star. ‘This is the first time he has coached world class players so you have to give him a chance.
‘You can’t just spend £200m and expect it to happen overnight. It takes time, even when you have a squad full of talented players.
‘I don’t think he knows his best team and that is a big problem. He probably knows the back five, N’Golo Kante and Mason Mount. After that, it’s like bingo… When you’re under pressure and not winning games you chop and change every week looking for answers.
‘But he needs to go back to basics and stick with a set team for three or four games so they can find some consistency. Don’t worry about keeping everybody happy. There’s only one person leaving the club unless you start winning.
‘And no disrespect to Olivier Giroud or Tammy Abraham though, but you’re not winning the league with them starting, and that needs addressing.’