Ander Herrera one of 36 footballers facing jail and six-year football ban over alleged match-fixing scandal.
The Spanish star is accused of match-fixing in May 2011.
During his time at Zaragoza, he is alleged to have deliberately lost against Levante.
And Spanish state prosecutors said they are aiming for a two-year jail sentence and a six-year ban from football for the United ace.
Two-year sentences are normally suspended in Spain for first-time offenders, meaning Herrera would escape jail.
However, lawyers have demanded stricter penalties to those found guilty – which includes 35 other football players.
And Spanish publications have reported that a four-year prison sentence was demanded by La Liga lawyers.
As well as Herrera, other high-profile footballers include Atletico Madrid star Gabi and former Middlesbrough striker Cristhian Stuani.
Manager Javier Aguirre is also being prosecuted.
It has been claimed that nine Zaragoza players, including Herrera, were paid cash by the club which was returned so it could be handed over to Levante players.
The terms Levante agreed to lose the match so Zaragoza would avoid relegation, condemning Deportivo La Coruna instead.
The case was reopened last month after an earlier decision to shelve it.
Herrera said earlier this month: “As I stated back in 2014 when this issue was raised, I have never had, and never will have, anything to do with manipulating match results.
“If I am ever called to testify in a judicial hearing, I will be delighted to attend as my conscience is totally clear.
“I love football and I believe in fair play – both on and off the pitch.”