The People says Diego, 23, wants to come to the Premier League and Eriksson has made contact with him through his family and advisers. The player is also open to joining City.
Eriksson is keen to land the 20-cap star, who could bring his pal Elano back to life and give City more goals from midfield - he has notched an amazing 25 goals in just 57 appearances for Bremen.
Whether City's Thai owner will bankroll the deal, however, remains to be seen. It's reported Thaksin and Eriksson are at odds over some of the potential signings being discussed.