The Mexican, 22, was set to make a third title defence against Argentina’s unbeaten Roberto Domingo Sosa at the Hard Rock Hotel and Casino in Las Vegas.
The fight will still go ahead but even if Sanchez wins the title will remain vacant; if the 28-year-old Sosa wins, he will be crowned IBF junior bantamweight champion.
The confusion arose because of the time at which Sanchez appeared for his second weigh-in on Friday – he had initially been one pound over the 115lb limit, but under IBF rules had two hours to lose the weight.
But, unbeknown to Sanchez and IBF supervisor Aaron Kizer, the US state of Nevada has different rules, with fighters only given one hour to make weight.
So when Sanchez returned in what he thought was good time, local boxing authorities had already declared him overweight, despite Kizer announcing he had made weight.
"He said he thought he could round it down to 115, but the IBF headquarters told him later he couldn't and that he had made a mistake," Top Rank promoter Lee Samuels told ESPN.
"Obviously, Sanchez and his team were not happy because they had been told him his weight was okay on Friday."
Sanchez won the belt off Rodrigo Guerrero in February 2012 and successfully defended it against Juan Alberto Rosas and Rodel Mayo.
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