One of the game industry's most prominent and powerful players has left the company where he started his career almost 20 years ago. This morning, Microsoft senior vice president and chief Xbox officer Robbie Bach sent an e-mail out to the press announcing that Ed Fries, Microsoft Game Studios' vice president of games publishing, was leaving his post.

In the e-mail, Bach said that he had "reluctantly accepted Ed's resignation, who after 18 years of service to Microsoft, has made the decision to leave the company and pursue other goals." Bach added, "Although I'm saddened by Ed's departure, the occasion provides a unique opportunity to celebrate his impressive contribution to the company--a career that spans nearly two decades." No reason for the resignation was given.

For now, Fries will be replaced by MGS COO Shane Kim, who, Bach says, "will serve as acting chief of Microsoft Game Studios until such time that a permanent successor can be named."

In a conversation with GameSpot today, Bach revealed that while he and Fries had been discussing the move for weeks, it was only last Friday that Fries announced his decision was final. The departure was official as of yesterday.

Bach confirmed that Fries had "removed himself from the day to day agenda," at Microsoft, and that Kim was firmly entrenched in his new role as acting chief of the studios. Last Friday was Fries' last day in the Microsoft office.

Kim told GameSpot his primary focus was "to make sure the organization doesn't skip a beat…to make sure we continue to execute on our plan." He added his immediate mission now was to "take stock of the organization and continue to produce awesome games in the future." As for Kim's future role within the organization, Bach did say that events "may lead to Shane being the permanent head" of the organization.

Fries began his career at Microsoft in 1985 as a lowly intern in charge of online tutorials. Ten years later, he was put in charge of the Microsoft's games division, and brought an impressive group of developers--including Ensemble Studios' Bruce Shelley and Big Huge Games' Brian Reynolds. Fries was also at the helm during the Xbox launch in 2001, and was instrumental in Microsoft's acquisition of Halo-makers Bungie.