The manager believes his side will still be able to compete this season and has the infrastructure in place to succeed.
The likes of Diego Costa and Filipe Luis, key cogs in the capital club's title success last season, have been sold to Chelsea, while Thibaut Courtois has returned to Stamford Bridge after a loan spell.
However, the Spanish champion has signed Mario Mandzukic and Antoine Griezmann and Simeone feels it will still be capable of challenging.
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"We're working from top to bottom," he said at a news conference. "Now we will return to Madrid and find another group and we'll slowly prepare for the start of the season.
"Today we have the same structure we have had for three years. Obviously our attacking potential made us grow, but the structure is the most important and ours is solid."