The first time I saw Carlos Zambrano pitch was in spring training in 2001. He was 19 years old and had pitched mostly in relief for Triple-A Iowa in 2000 and didn't appear headed for the major leagues for another year or two.

The heat he threw and the energy he showed on the mound screamed out to me, "future closer".

Maybe that would have been better for the man Cubs fans have come to know as Big Z; he could have been K-Rod, or Jose Valverde, or any one of a number of successful closers who show histrionics on the mound after they retire three batters in the ninth inning and close out a victory for their team.

Instead, he transitioned to starting and was fast-tracked through the system. He was in the Cubs' rotation to stay by August 2002, barely 21 years old, and the next season he, along with Kerry Wood and Mark Prior, led the Cubs to an improbable playoff berth and a NLDS win over a powerful Braves team.

Big Z's career path went pretty well until 2008, highlighted that year by the no-hitter he threw on September 14 against the Astros in a game hastily rescheduled for Miller Park in Milwaukee by Hurricane Ike.

He also entertained Cubs fans with his prowess at the plate -- his 23 career home runs are now ninth all-time among pitchers. But there were some disturbing incidents that began to become more frequent -- in 2007, he and catcher Michael Barrett fought in the dugout, an incident that resulted in Barrett being traded within weeks. The next year, he got into it with umpire Mark Carlson and heaved a ball 300 feet, nearly into the left-field bleachers at Wrigley. And last season, he had what I termed at the time in a tirade directed at his mild-mannered teammate Derrek Lee.

For that, he got placed on the restricted list (with pay) and anger-management classes. When he returned in August 2010, he was lights-out, going 8-0 over 11 starts with a 1.41 ERA. Hopes were high for him to keep that going in 2011.

Instead, he's been erratic this season, occasionally flashing his previous good form (as in this solid outing against the Padres on April 18) but mostly being mediocre, occasionally bad, and finally melting down again Friday night in Atlanta. He allowed five home runs (tying a Cubs team record), was ejected after throwing at Chipper Jones, and then cleaned out his locker at Turner Field and said he was "retiring".

The details don't really even matter any more, I don't think; Zambrano is acting like a child. The Cubs have done just about everything they can to help "fix" him; they also reportedly offered him around before the July 31 trading deadline with no takers, even with the Cubs eating much of his contract, which has a year left at $18 million. Some whisper that Big Z, who just turned 30 in June, has lost some zip on his fastball. He never really was a power pitcher; his best years, from 2003-2006, and some of his best games, came when he relied more on a power sinker.

But now, the Cubs may have no choice but to simply eat the money and release him, if he doesn't follow through on his threat to retire Friday night. Cubs management has repeatedly given him last chances. He appears to have walked out on his final last chance; more than anything else, it's sad that a man who has the energy and passion that Carlos Zambrano does was never able to harness that into his pitching.