An appeal to the Court of Arbitration for Sport brought an early end to the original two-window embargo last week, enabling the Blues to become active participants in the transfer market.

An inexperienced squad reached the UEFA Champions League last 16 with Wednesday (AEDT) 2-1 home win over Lille and could now be reinforced.

Chelsea scored 11 times in their six Group H games and have notched a further 31 goals in the Premier League, but head coach Lampard outlined plans to seek a replacement for Eden Hazard.

"I think it will be a bit fluid," Lampard told BT Sport after beating Lille at Stamford Bridge.

"There will be discussions that go on from now about where we can strengthen, because of course with Eden leaving we lost a lot of goals, a lot of creation in his particular position.

"What I'm talking about today is that we missed some chances and I think we can probably look at strengthening and pushing and getting maybe more competition in those areas."

First-half goals from Tammy Abraham and Cesar Azpilicueta confirmed the club's progression in Europe, although the result was made narrower than it should have been by Loic Remy's belated response in the 78th minute.

The Blues, who finished second in the group behind Valencia, would have slipped into the Europa League had Lille pinched a late equaliser.

Lampard said: "With the youth, we understand those bumps in the road will come, whether individually or collectively.

"I push them a lot, I'm quite tough with them, and I want them to work and improve. But at the same time, you do have to be a bit patient. That's where the balance of the team and the squad is important – the older, more experienced players do help them.

"We have got a good balance but I think today was a strong sign of how much work we have to do. It should have been a game that was finished much earlier.

"It's been a little bit the story of our season at times and that's the biggest thing, for me, we need to improve."