Blues summer signing Ziyech pulled up in the first half of Chelsea’s 3-1 win at Stamford Bridge on Saturday evening and was replaced by Christian Pulisic.
Asked for an update on Ziyech after the victory, Lampard said: ‘It was his hamstring, he felt it go.
‘We will have to find out what degree it is over the next few days.’
Lampard added: ‘Leeds are a superb team. They are pretty unique in their style and they’re well coached.
‘We knew it was a big task. Character-wise and performance-wise, on lots of levels, I’m absolutely delighted.’
More to follow…