The 24-year-old admits he was flattered by the interest from the Premier League side but insists he never spoke with the Red Devils and is happy to stay at Athletic Bilbao.
Herrera, who admits he was flattered by United's interest, also claims that three lawyers - later reported to be 'imposters' - who were seen entering the offices of the Spanish football league [LFP] were not acting on his behalf.
"I reached no agreement with United. I am proud they made an offer for me, and that Athletic wanted me [to stay]. I do not feel used by United, they made a formal offer. Athletic did not want to negotiate, I value that," Herrera told reporters. "I feel very flattered to see that one of the biggest clubs in the world like United made an offer for me.
"The lawyers who were at the LFP offices did not represent me. I do not know who they were. I don't discuss hypotheticals. I am just telling you how things were. At no moment did I speak with United. They had to pay the 36 million euro clause and then seduce me more than Athletic. I never saw myself elsewhere."