It's still early to dismiss even Barcelona who is 10 points behind them - let alone Real, but this season is the best chance Atletico will probably have in the near future.
They have conceded only 6 goals in 15 games (2nd is Sevilla with 11) and both Suarez and Felix are in good enough form to carry them on in attack. I hope they do win it, I dislike their football but they are the best team this season.
In my opinion, Real Madrid is the one and only team that will be able to disrupt the Atletico position because both of them have an equal opportunity to become La Liga champions.
So far, Real Madrid's performances can be said has been good enough, with 11 wins and only lost 3 times, Real Madrid is still in the race. Most likely the second match between Real Madrid and Atletico will be a crucial moment to fight for the champion seat.
For Barcelona, they actually still have a chance, but because their performance has not improved either, so their chances are smaller than Atletico and Real Madrid. Moreover, they are very dependent on Messi, so if in future matches Messi can not be able to play again because of injured or something else, then Barcelona's opportunity to win the league is very small.