Diego Simeone's men defied the critics last season when they broke the domestic strong hold of city rivals Real Madrid and Barcelona to clinch a first La Liga title since 1996.
Atletic underwent several changes during the close-season, though, with starts such as Diego Costa, Filipe Luis and David Villa departing.
In their place Simeone signed proven talent with the likes of Mario Mandzukic, Antoine Griezmann and Alessio Cerci all moving to the Spanish capital.
Atleti have shown that they still possess the quality to mix it with the league's star names after defeating Real 2-1 at the Bernabeu earlier this month.
However, Atleti, who sit third, have already fallen four points behind Barcelona after they were held to a 2-2 draw at home to Celta Vigo on Sunday.
The new campaign may still be in its infancy, but skipper Gabi said the club can ill-afford to slip up at the Estadio de los Juegos Mediterraneos.
"It's very important Wednesday's game," he told Marca. "With a draw [against Celta] we have to win and I think we will get a result. This game is a final."
The draw with Celta followed a disappointing 3-2 loss at Olympiacos in their UEFA Champions League opener last week and centre-back Miranda stated the team must do more to shore up the defence.
"It isn't normal to concede five goals [in two matches] but we are working hard to correct what we have done wrong in these two games, and it probably won't happen again," he said.
Atleti could welcome back striker Mandzukic who rejoined training after undergoing surgery on a broken nose, while Cristian Rodriguez (calf) is hoping to be back in contention and coach Simeone continues to serve a touchline ban.
In the corresponding fixture last season Almeria ran out 2-0 winners in February and Francisco Rodriguez's side will hope to build on a solid start.
After finishing just outside the relegation zone in 17th last term, Almeria have taken five points from their opening four matches this term and occupy 10th place.
Impressively, their first win of the new campaign arrived on Sunday in a somewhat surprising 2-1 triumph at Real Sociedad, despite playing out the closing stage with 10 men after full-back Sebastian Dubarbier was sent off in the 79th minute.
Dubarbier will now sit out against Atleti and 32-year-old left-back Mane could fill the void.
"The only thing I can do is work every day to my fullest to try to start," he told the club's official website.
"Right now I am willing and prepared if the coach considers it appropriate for me to play and if so I will try to make the most of my opportunity."