Romeo Lavia's last condition has been announced and it looks like he won't be able to play in the remaining part of the season either. Chelsea are really unlucky with their transfers. They have been struggling with many injuries for a long time. If the injury problem wasn't this serious would they be better? I can't be confident about it as well. 
Lavia injury source: Transfermarkt
It is like all that money spent is for nothing. They are still in the middle of the league standings. Zero difference between last 2 seasons...
I checked on Google and Roméo Lavia only played once for Chelsea and don't know for sure whether it was full time or just as a substitute so Chelsea have had no luck with player transfers this season because not only Roméo Lavia was injured but several of their new players experienced the same thing even though not a long injury like Roméo Lavia.Lavia injury source: Transfermarkt
It is like all that money spent is for nothing. They are still in the middle of the league standings. Zero difference between last 2 seasons...
Chelsea felt a loss because the value of Roméo Lavia was quite high when Chelsea bought him and that was because there were two clubs who made offers to Southampton to get this player, with the long injury suffered by this defender, it is very possible for Chelsea to be aggressive again in the transfer market because so far their players have not performed as expected.