Chelsea have been linked to Bayern Munich striker Mario Mandzukic several times over the past few months, in addition to Diego Costa. There have also been reports out of Spain linking Romelu Lukaku to Atletico Madrid as a replacement for the Brazilian-born Spanish international.
With one tweet this morning, both of those rumors can probably be safely put to rest:
The presence of Mandzukic at Atletico means that's the Spanish capitol is no longer a realistic destination for Lukaku. It also probably makes Chelsea a bit more likely to keep Lukaku in London, as one of the best forward options on this summer's market is no longer available.
That said, there are other striking options out there that Jose Mourinho and Michael Emenalo could be looking at, and if they weren't sold on Lukaku before, they'll probably still be sniffing around for another center forward.