Barry Bonds, Major League Baseball's all-time home run leader, appealed his obstruction of justice conviction on Thursday.

In a 70-page appeal filed with the 9th U.S. Circuit Court of Appeals, Bonds' lawyers argued that the conviction was based on an "invented legal theory" that did not amount to criminal conduct.

The lawyers said the conviction should be overturned because of many factors involved in the trial.

"The government should not be allowed to salvage this misguided prosecution by minting a new theory of obstruction and creating a new criminal offense," Bonds' lawyers wrote. "Mr. Bonds' conviction cannot stand."

Bonds, 47, was convicted in April 2010 of obstructing justice during his December 2003 testimony before a federal grand jury probing the Bay Area Laboratory Cooperative steroids scandal. Bonds was found not guilty of three perjury charges.