Conte already has a player on his books with the single-minded approach of Lukaku but Costa, an aggressive livewire, doesn’t appear to be the easiest player to look after and tends to drift in and out of form. He scored 20 goals in the Premier League last season while spearheading Conte’s attack but with Eden Hazard a very individually minded player, Chelsea might offer more going forward (and defend better) with a more team-focused player alongside him.
With Morata through the middle, Chelsea now have a clever striker capable of adjusting to circumstance on the pitch and who can help construct the quick passing moves that Hazard, Willian and Pedro are so adept at playing, making full use of that dynamic frontline. Lukaku is not the kind of player to spring a one-two move together, nor is he able to sprint away from defenders on the counter-attack like Morata can.
Costa is quick too, but batters his way into goalscoring positions and forces defences open with sheer determination rather than crafting opportunities with skill. An absolute nightmare to play against, Costa just isn’t the best at link-play between forwards and this is perhaps the main reason he hasn’t really performed as hoped at international level with Spain, and another reason Conte isn’t desperate to hold onto him.