By ESPNSTAR.com staff
The defender joined the German side for a fee of €8 million and leaves Vicente Calderon after playing there for five seasons in La Liga.
He bemoaned the lack of opportunities available for youth team graduates that has even seen famous players such as Raul leave the club. The Real Madrid legend had been part of the cantera team that had won the national reserve league title in 1994 but was forced to leave following the closure of Atletico's youth academy.
Dominguez also stated that he did not enjoy having to compete against defenders signed from other clubs on an annual basis.
"My old club never bet much on homegrown talent," Dominguez told Radio Marca.
"Every year, they brought in a new centre-back to compete with me for a spot.
"I've never been afraid, but I felt it was time for a change this year."
Atletico's academy is a popular hunting ground for the top European clubs as they have churned out talented players such as Fernando Torres, Sergio Aguero and David de Gea.
Recent reports link another promising youngster with a move abroad with Manchester United said to be interested in 18-year-old goalkeeper Rodrigo Alvarez.