In a manga, two American boxers are talking about a guy they used to know who now lives in Japan.
Boxer A: あのブルドッグがリングに上がるって本当かよ。
Boxer B: ああ。ここ数年噂を聞かねェと思ったらボクサーになってたんだよ。日本でな。
I think 数年〜の噂を聞かない means "I haven't heard of 〜 for some years", so maybe the rough translation of the sentence is "I haven't heard of him for some years, it seems that he's become a boxer". But what is the meaning of 思ったら here? Thank you for your help!