Costa, who has been in magnificent form this term, scoring 25 goals in 30 games in La Liga, has been linked with a big-money move away from the Spanish capital during the summer (as per The Independent), and is a large part of the reason why Atletico are still competing in the Champions League and La Liga.
There is no question that his presence in Diego Simeone's side is crucial, but there are reasons to believe that his injury might help the team in the long run.
Although it would never be said, Atletico's main focus this year should be on winning the Spanish league title. Winning the hearts of football fans around the world as the underdog has brought them onto the world stage, and challenging the "big two" of Barcelona and Real Madrid for supremacy in Spain should take precedence over an unlikely Champions League win.
It is Diego Simeone's first managerial role at a European club and his influence on the team and the club have been nothing short of revolutionary.
From dealing with the loss of their talisman Radamel Falcao last summer to taming Diego Costa and turning him into one of the most sought-after players in the world, his work at the club must be applauded.
However, Diego Simeone's lack of squad options, which results in little or no variation in his team's line-up, has led to very little recovery time for his top players.
Diego Costa has played in 30 out of 31 of Atletico's La Liga games this year, six out of nine of their Champions League fixtures and five out of eight of their Copa del Rey fixtures.
He has played 3,690 minutes of football out of a possible 4,230 this year, which includes 90 minutes in Spain's 1-0 victory over Italy in March, in what was his debut for Spain.
Simeone's high-tempo, fast-paced style does not accommodate a lot of recovery time, and despite the fact that Costa is and will be needed in the last few weeks of the season, a well-deserved week off, whether injury induced or not, is necessary at this point of the season.
Atletico play Villareal this weekend in La Liga, and it could encourage Simeone to test some fringe players who haven't been given chances this year: Players like Diego Ribas, Raul Garcia and Jose Sosa, who have impressed in the limited action they have seen.
It could also force the Argentinian to play a different tactic to his preferred 4-4-2, and the reliance on David Villa could become more apparent. Another consequence of Costa's injury that could help in the long term.
Villa has not scored in Atletico's last four games, and the onus is now on the Spaniard to refind his finishing touch to push Atletico over the line in the absence of his teammate, Costa.
The reality of a Champions League/La Liga double is becoming all the more real for Diego Simeone and his charges, but all eyes will be on Atletico and Costa when Real Madrid and Barcelona start applying more pressure in domestic competition.
A rested-and-ready Diego Costa is essential when that pressure comes.
(All stats provided by Transfermarkt.com)