2. Moussa Dembele
It is quite evident that without Abraham, Chelsea struggle quite a lot. It was seen against West Ham when they failed to score any goals and subsequently lost the match. Chelsea's other forward options are Olivier Giroud and Michy Batshuayi, but both aren't suited enough to lead their attacking line.
Dembele is a fierce striker, something Chelsea have missed since the times of Diego Costa. Unlike Giroud and Batshuayi, Dembele has a much better conversion rate, and would significantly improve the Blues in front of goal.
Dembele has scored a highly impressive ten goals from 15 league matches this season and has been duly praised. The Frenchman joined Lyon in the summer of 2018 and has seen his value increase significantly after that.
Given that Chelsea have had striker problems for a long time, this is a move that makes sense for all parties involved. Dembele being such an essential player for Lyon might make it a bit difficult for Chelsea to get him to Stamford Bridge.
However, if Lampard and co succeeded, then it will surely pay dividends.
Alternate option: Krzysztof Piatek (AC Milan)