MLB commissioner Bud Selig is leaning toward suspending Jason Giambi if he does not cooperate with the ongoing investigation into steroid use, according to a report Wednesday on the USA Today Web site.

The report cited "a high-ranking Major League Baseball official" who said that Selig wants Giambi's decision by Tuesday.

Selig said last week that Giambi could avoid discipline for comments made to USA Today if he cooperated with former Sen. George Mitchell's investigation.

"I was wrong for doing that stuff," Giambi told the paper last month. "What we should have done a long time ago was stand up — players, ownership, everybody — and said: 'We made a mistake.' Steroids and all of that was a part of history."