“I want to express my deepest gratitude to Stevie for all his help, but I think it’s time for a change,” Tiger Woods said on his website of parting ways with longtime caddie Steve Williams. (HANS DERYK/REUTERS)

It’s a poor workman who blames his tools, and caddie Steve Williams was certainly one of Tiger Woods’s most important tools.

Woods won 13 of his 14 career major titles and 72 tournaments with Williams toting his clubs the past dozen years. That’s a nice living for a golfer and by extension, for his caddie. But as Williams himself pointed out Wednesday, the last 18 months in Tigerland haven’t produced a lot of fun (or funds). Woods has gotten divorced and injured, he’s been treated for a sex addiction, he’s fired and hired a swing coach, he’s tried and failed to return to form . . . he’s a mess.

Williams, who more often protected Woods from fans and the media than advised him on club selection, waited patiently through all this. He hinted in an interview with Television New Zealand that he’s not been paid during this period, either, saying it’s been hard on his family. Caddies are paid based on their golfers’ success, so fiscally that makes sense.

So when Adam Scott called asking for Williams’s help, Williams asked Woods for permission, Woods said go ahead . . . and then fired him a few weeks later. Woods told Williams his services were no longer required earlier this month at the AT&T National, but Williams kept quiet until Woods issued a statement on his Web site. Then Williams said, “You could say I’ve wasted the last two years of my life.”

Of course, Williams played a far more important role in Woods’s life than caddie — he was also Woods’s friend. And friends are hard to come by in Woods’s world, where nearly everyone has more than one motive for wanting to get close to you. His friends seemed to be other golfers, and after word got out of his many, many infidelities, some of them walked away. If you socialize with golfers, you socialize with their wives as well. It’s an insular world and a guy with Woods’s track record isn’t going to be welcomed back into it anytime soon.

Williams was one of the guys who stuck by Tiger. He may have expressed his disappointment in Woods’s behavior to Woods — he says he did — but he remained friends with him. Even after all his years of success, Woods still comes off as stiff and wooden, in commercials, in media interviews, in his painful TV apology. Think about the times you’ve seen Woods smile or laugh; I’m betting Williams was standing next to him, whispering in his ear. It’s one of the few hints we have that Woods might actually have a personality and a sense of humor.

The conspiracy theorists among us say this is one more sign that the left leg injuries that have crippled Woods’s game are more serious than he will admit and that his career is finished, even if he gets Benny Goodman as a swing coach and Bagger Vance as his looper. He’s done, and letting Williams go was the kind thing to do.

Or was he just angry or hurt that Williams asked to caddie for Scott, that he saw it as a betrayal of their relationship? (And if that’s the case, then let’s pause for a moment to enjoy the irony of Tiger Woods feeling betrayed.) It also speaks volumes for Woods’s popularity that public opinion seems to be squarely on Williams’s side, despite the fact he was never the most popular caddie on tour.

But in the end, the truth is probably somewhere in the middle. Woods may be rebuilding himself from the ground up: his knee, his swing, his bag, his new girlfriend. Perhaps he’s divesting himself of all reminders of his previous life. That seems far more likely than Tiger Woods giving up on himself. On others, yes, but not on himself.