When James left Cleveland for Miami as a free agent in July 2010, Gilbert famously promised in a letter to disappointed Cleveland fans that his Cavs would win a championship before James got one with the Heat.
Well, that ended in June when James, capping his third MVP season, led Miami to a finals win over Oklahoma City.
"Looking back now, that probably was not the most brilliant thing I've ever done in my life,'' Gilbert said Tuesday.
Relaxed and wearing a wine-colored sport coat, Gilbert spoke to reporters on a number of topics before the Cavs' opener against Washington.
When the subject turned to James, Gilbert said he would have done some things differently two years ago, most notably his guarantee.
"If you're going to predict something that doesn't happen and you're going to do it publicly, you'd for sure take it back,'' Gilbert said. "When that happened when they won, it was the end of the end of the end of that whole thing. Now there's nothing more to talk about. In a way it was like a little bit of a relief. If they didn't win it, it would've been still another thing of who's going to win it (first)?''
Gilbert said James' departure taught the Cavaliers a valuable lesson, one that Oklahoma City seemed to have learned recently in its decision to trade James Harden to Houston. When the Thunder realized Harden was not going to accept a long-term deal, the club traded him before losing him as a free agent.
In hindsight, it's probably what Cleveland should have done with James.
"The key thing, whoever you are and wherever you are, you can not wait,'' Gilbert said. "The big lesson was if a player is not willing to extend, no matter who they are, no matter where they are playing, no matter what kind of season you had, you can not risk going into a summer and having them leave in unrestricted free agency and get nothing back for it.
"It's not the player's fault. That's on ownership. Had we done that, the whole thing would have been crafted as I'm sure the player or whoever would have said, `Of course I would have stayed. You guys screwed up and ruined the whole franchise.' You're in a no-win situation.''
Gilbert was also asked about another shift of power in the NBA with the Los Angeles Lakers adding superstars Dwight Howard and Steve Nash during the offseason. Gilbert doesn't have a problem with the idea of megateams, and said even ones with a surplus of talent are not assured of winning.
"I think a competitive league is better than a non-competitive league,'' he said. "You never know, there could be surprises. We'll see what happens this year.''