The Athletic Bilbao star was the subject of a €27 million bid from the Premier League champions, but the Liga outfit insisted a sale would have to be forced be a release trigger
The 24-year-old was one of a number of central-midfield targets Moyes failed to lure to Old Trafford, with Thiago Alcantara preferring Bayern Munich and Cesc Fabregas opting to stay at Barcelona.
Moyes has confirmed an offer of €27 million was lodged, but Athletic were only prepared to part with their talisman if his €36m [£30.6m] release clause was triggered - demands the United boss deemed unsuitable.
"The stuff about Herrera, we made an offer for €27 million and we were never going to go to the buy-out clause," Moyes told reporters.
"All the rubbish that was talked about that - with people going in, they were never working on behalf of us. Never at any time did we increase our offer."
Moyes, though, was bullish when questioned on his other failed attempts at recruiting players, and insisted that Marouane Fellaini - who joined in a deal worth £27.5m in deadline day - was always in his mind, with a pursuit of Leighton Baines preventing earlier confirmation.
"Did we miss out on a lot of targets? No. Was it disappointing? No. We tried to get some great players to join Manchester United and for different reasons we couldn't get them.
"In the end we knew at the start of the window that we liked Marouane Fellaini, you've heard my explanation on why we didn't do it sooner."