MINNEAPOLIS — The head of a Minnesota sports memorabilia company was charged Thursday with orchestrating a scheme to sell fraudulent sports merchandise online, including fake baseball jerseys he claimed were worn during games by Alex Rodriguez, Mark McGwire and Albert Pujols.

U.S. postal inspectors arrested Steven Jensen, chief executive of Plymouth-based Vintage Sports Authentics, during a sports collectors’ convention in Rosemont, Ill. He is charged in federal court in New York City with one count of mail fraud and one count of wire fraud.

Jensen, 40, of Osseo, and his company are accused of knowingly auctioning off jerseys between July 2007 and last month that were purportedly “game used,” worn by prominent baseball players, but were not authentic.

If customers independently learned the jerseys were fake and returned them, Jensen allegedly re-auctioned them, authorities said. The U.S. Postal Inspection Service did not immediately put a dollar figure for the alleged scheme.

Messages left at Vintage Sports Authentics were not returned Thursday. A message seeking comment also was left at a telephone listing for Steven Jensen in Osseo.

Thomas Boyle, an assistant inspector-in-charge with the postal inspection service, said no merchandise was seized from Jensen’s booth at the National Sports Collectors Convention on Thursday. Authorities also searched his company warehouse in Plymouth.

Vintage Sports Authentics auctions sports memorabilia “purported to be authentic and genuine,” according to the criminal complaint filed in New York.

In July 2007, the complaint said, one customer in the Bronx paid more than $3,000 for a home Seattle Mariners jersey the company said was worn by Rodriguez during the 1995 season. The customer brought the jersey to a sports memorabilia show in New Rochelle, N.Y., in January 2010 for Rodriguez to sign.

An authenticator at the show determined the jersey was fake because the name plate fabric was different from the rest of the jersey, the complaint said.

The complaint said Jensen stood by the jersey’s authenticity when approached by the customer, who eventually returned the jersey after a former Mariners equipment manager examined it and also concluded it wasn’t genuine.

Vintage Sports Authentics re-auctioned the jersey online last February, falsely stating it was the real thing, the complaint said.

In another online auction, an undercover postal inspector paid $477 to buy an away Oakland Athletics jersey advertised as being worn by McGwire in 1997. The agent spoke with several people to determine the jersey was fake, including McGwire, according to the complaint.

The postal inspector showed McGwire a list of other memorabilia offered by Vintage Sports Authentics, including a Home Run Derby jersey purportedly worn by McGwire during the 1999 All-Star Game. McGwire told the agent he still has his Home Run Derby jersey, the complaint said.

The agent told Jensen the jersey was fake and returned it, and his company offered it online again as genuine, the complaint said.

Vintage Sports Authentics also offered an away St. Louis Cardinals jersey in February said to be worn by Pujols in 2002. But Pujols told officials he still possesses the only two away Cardinals jerseys issued to him for the 2002 season.

Christopher Cavalier, chief executive officer of Game Used Universe, which hosts online auctions and collector forums, said sports memorabilia collectors must educate themselves and examine jersey stitching, lettering, manufacturer’s tags and other details to determine an item’s authenticity.

“It’s an unregulated industry,” Cavalier said. “There is a lot of money to be made and if people aren’t educated, the collector is the one who is going to lose out.”