The Mexico international joined Atleti from Porto in the summer on a free transfer, after Rodri left for Pep Guardiolas Manchester City in a €70m deal.
However, he has found himself largely on the bench, playing just 391 minutes for Los Rojiblancos this season, starting only four times.
Speaking to Marca, Herrera admitted he has wondered whether he was right to leave Porto. When asked if ever thought he had made the wrong decision he said: "It is normal, it is impossible not to think that.
"I knew what could happen, or what was happening because today I am being more taken into account and taking more minutes. I knew it was the best decision for me in every way."
The 29 year-old was captain of Porto for three seasons and won one Primeira Liga title with the Portuguese side.
Despite this, he has found it tough to break into an incredibly talented Atleti midfield that includes the likes of Koke, Saul Niguez and fellow summer signing Marcos Llorente.
Herrera remains confident however, that he can establish himself as a starter at the Wanda Metropolitano, and insisted there is more still to come.
"Now that I have had more minutes I am beginning to enter the rhythm of the team, of the tasks that the coach wants and trying to connect more to his system. Hopefully both me and the team will grow and approach our best version all for the collective good."
Atletico Madrid have made a slightly underwhelming start to this La Liga season, scoring just 15 goals in their 13 games so far.
Despite this, they remain just one point of leaders Barcelona, and will be hoping that they can challenge for a first league title since 2014.