In his report last month on drug use in baseball, George Mitchell had recommended the formation of the unit. Adopting another of Mitchell's recommendations, MLB is establishing a tip line for team employees to make the commissioner's office aware of violations of drug, betting and other rules.

MLB said the unit "will have broad authority to conduct investigations." The limits of the unit were not immediately clear. Will it place moles in clubhouses? Will it secretly tail players away from ballparks?

Dan Mullin, a former New York City Police Officer who had been in baseball's senior director of security operations, was appointed vice president and head of the unit. George Hanna, a former FBI employee currently in baseball's security department, was appointed senior director of investigations.

Mullin was not available for comment, baseball spokesman Rich Levin said.

"The department of investigations will have critically important responsibilities in protecting the integrity of our sport," commissioner Bud Selig said.

It was unclear whether the activities the unit could participate in would have to be negotiated with the players' association. Under labor law, terms and conditions of employment are subject to collective bargaining.

"We learned about this late last night. We had no role of any kind or sort in it," union head Donald Fehr said. "After we digest it, to the extent we have questions and things we want to raise, I'm sure we'll be doing that."

MLB will require all employees of the team and the commissioner's office to report any information on the possible use of performance-enhancing drugs to the head of the department of investigations. All team baseball operations employees will be required to sign annual statement that they have no undisclosed knowledge of drug use, possession or distribution by players or other team employees.

This week, MLB adopted several other recommendations made by Mitchell, such as background checks and random drug tests for clubhouse employees; logging all packages sent to clubhouses; and permanent credentials for drug testers.

Selig has said some of the recommendations are subject to collective bargaining, such as moving responsibility for drug testing to an outside body. Lawyers for MLB and the union had a preliminary discussion this week.