Baseball star Miguel Tejada is expected to plead guilty tomorrow to charges that he lied to Congress about steroid use in the Major Leagues, a source familiar with the case tells FOX News.

The charges are not about any personal steroid use. Instead, prosecutors allege that Tejada, currently with the Houston Astros, lied about another player's actions when he was with the Oakland Athletics.

According to "criminal information" filed in federal court today, Tejada told a congressional committee investigating drug use in professional baseball that he "never heard" any of his fellow players talk about steroid use. And, in a 2005 interview with congressional investigators, he said he "didn't know any player" on the Athletics who used steroids.

But, according to prosecutors, Tejada had in fact had "several conversations" with a player two years earlier about that player's use of steroids. So, prosecutors insist, Tejada "unlawfully withheld pertinent information from the committee."

The other player is identified in court documents only as "Player #1." However, in the extensive Mitchell Report released in 2007, the Athletics' Adam Piatt was quoted as saying he talked with Tejada about steroid use.

Tejada, who was voted American League MVP when he played with the Athletics, is scheduled to appear in U.S. District Court in Washington at 11 a.m. tomorrow.

According to today's filing, the case was referred to the Justice Department in January 2008, after the Mitchell Report contained information that "appeared" to contradict Tejada's previous statements. In referring the case to the Justice Department, the House Oversight Committee said it was especially concerned" about the matter because Tejadas statements helped to direct the course of its investigation in 2005.