The coach of the recently-promoted side admitted that contact had been made after the defender was reportedly recommended to the club by Jurgen Klinsmann
Following massive financial issues, the Scottish club has been forcibly relegated to the Scottish fourth tier and the United States international was recommended to the Bundesliga club by the coach of the national team, Jurgen Klinsmann.
Frankfurt coach Armin Veh did concede that contact had been made with the 33-year-old, but insisted the decision will be made over his head.
"Yes there was contact. But I will not comment on any names as other people are responsible for this," Veh told Bild.
Bocanegra, who has been capped by his country 103 times, could be available on a free transfer due to a partial waiver of his salary at Rangers last season, and he admitted interest in a move to Germany.
"The German Bundesliga now excites me a lot as well..." Bocanegra said.