I thought they were nuts.

When the Diamondbacks signed Randy Johnson to a four-year, $53 million contract four offseasons ago, I thought Jerry Colangelo's ego had escaped from its cage and run crazed over the free-agent marketplace. Four years at $13 million-plus apiece for a young Greg Maddux would be one thing, but for a 35-year-old power pitcher with a recent history of back problems? Was Arizona insane?

	Randy Johnson is 81-27 with a 2.48 ERA over the last four years with the Diamondbacks.

I offer this mea culpa because embarrassment loves company; I was not the only one who questioned this decision. Perhaps we should all get together and toast our omniscience, because all the Randy Johnson contract has turned out to be is the best free-agent signing since Peter Seitz sneezed.

Le Grand Unit won his fourth straight National League Cy Young Award on Tuesday. Think about that -- four years, four times the best pitcher in the league, four times establishing himself as the best lefty since at least Sandy Koufax. Not bad for a "goofball," as Johnson has occasionally called himself.

It's hard to believe anyone doubted this, looking back. That's because we were looking at his back.

Of course Johnson had been a dominating force in the years before his injury, particularly his 18-2, 2.48 season in 1995 for the Mariners when he won his first Cy Young. But in 1996 his 6-foot-10 body, specifically his spindly spine, gave out: He went on the 60-day disabled list in May for an irritated nerve in his lower back, came back briefly and then succumbed to surgery on Sept. 12 to correct an extruded disc herniation. Back problems are a red flag the size of Kansas -- it was hard to know if he'd ever be the same pitcher again.

He proved he could be by returning in 1997 to go 20-4, 2.28 for the Mariners. But then in 1998, a walk year after Seattle picked up his $6 million option, Johnson sulked through the first half by going 9-10 with a particularly disturbing 4.33 ERA. He was traded to Houston, went an unreal 10-1, 1.28 the rest of the way, but people still had to wonder: Just what were they getting in this guy? How much was his psyche an issue? What role had his back played? And given that most pitchers start their decline by age 35, had his just begun?

The Rangers and their new owner, Tom Hicks, set the pace with an early offer of three years at $36-$39 million, with a club option for a fourth year. (Hicks heralded this as "by far the largest offer in the history of the organization." Insert chuckle here.) The Angels, Dodgers and Diamondbacks were also serious suitors.

The Astros offered $33 million for three years, but dropped out when Johnson wanted a fourth guaranteed year. Citing his past bad investments in pitchers Doug Drabek and Greg Swindell, Houston owner Drayton McLane said, "If for some reason Randy was not able to pitch at a high level in the third or fourth year, it just paralyzes the entire team because you have so much money wrapped up in one player who is not producing ... We just were not ready to take that risk."

The Angels took the next step by making Mo Vaughn the highest-paid player in the game at $80 million over six years. The Dodgers also were interested in free-agent righty Kevin Brown. So the Diamondbacks, whom many saw as the favorite for Johnson because he wanted to pitch near his Phoenix-area home, eventually pulled ahead for good with their four years and $53 million.

Johnson signed with a one-year-old club that had just gone 65-97. He immediately faced questions both over his choice of team, and the team's choice of him.

"People think I'm taking a step backward -- you know, 'He's not going to win,'" Johnson said. "Who are you to say I'm not going to win? None of you have ever been in my shoes and realized the expectations that I have in the game.

"I'm one of the winningest active pitchers in all of baseball right now. I've struck out more hitters in the '90s than anybody else. I've been able to pitch with anybody in the game. I don't know why anybody would think that's a bad investment."

Asked about the possibility of the Diamondbacks continuing to lose, Johnson glared, "I won't let that happen." He kept his word -- he led the team to 100 wins and its first NL West title in 1999, then a World Series championship in 2001 and the playoffs again this season. His dominance shows no signs of slowing down.

How could anyone have doubted this? In retrospect, Johnson's co-agent, Barry Meister, says that it really was only fans and media who questioned the signing -- teams that did their homework had no concerns at all. One of the bigger defusers was that the pitcher had already secured a $10 million-a-year insurance policy that was transferable to the team that signed him, with no exclusion for his back. (This was pre-Albert Belle, when insurance was far easier to secure.) So there was even less risk than at first glance.

"Initially some teams said, 'We want to ask about his back,'" Meister says. "I just told them to look at the Baseball Register. He went 20-4 as the Opening Day starter after having back surgery the previous September. People's first perception was that if he had a flaw, it had to be his back. But when GMs researched the issue, they found it wasn't one. Not one team conditioned an offer based on his back."

These are Johnson's pitching lines ever since:

Year	W-L	ERA	IP	H	BB	SO
1999	17-9	2.48*	271.2*	207	70	364*
2000	19-7	2.64	248.2	202	76	347*
2001	21-6	2.49*	249.2	181	71	372*
2002	24*-5	2.32*	260*	197	71	334*
AVG	20*-7	2.48*	1,030*	787	288	1,417*

* Led league

Johnson's four-year totals lead the National League in all three triple-crown categories, as well as innings. Assuming he wins this year, each one of those seasons will have been followed by Cy Young Awards. (This November's hardware would bring with it an extra $4 million, Meister said -- a $1 million bonus and $3 million added to his $12 million salary for next year.) Johnson's 81 wins from 1999-2002 lead the runner-ups, Schilling and Maddux, by a whopping 10; he has pitched at least 100 innings more than anyone else in baseball and struck out more than 400 than his closest competitor.

Johnson's back has been even less of an issue than the optimistic Diamondbacks could have hoped. In June of 1999 he did feel tingling and numbness down his left leg, but an MRI showed no damage and he didn't miss a start. He missed a start this May because of a strained lower back, and he did pitch relatively poorly his next several outings, but it caused no long-term problem.

At 39, Johnson is better than ever. In spring training he commented that as he got older he would begin to focus on efficiency over power. "I'm looking to get quick outs," he said. Mission accomplished -- in 2002, his pitches per plate appearance declined from 4.10 last year to 3.86, the lowest of his career. His 15.4 pitches per inning were also his lowest ever.

A few weeks after Johnson signed with Arizona, the Dodgers diverted all the hoo-ha and skepticism toward themselves by inking Kevin Brown to a seven-year, $105 million deal. However shocking, though, that contract was generally seen as less risky than Johnson's. The Orange County Register wrote, "A contract of five or six years with Brown, 33, could be a problem ... But the Dodgers made a four-year offer to Johnson, 35, which means they were confident he could pitch until he was 39, and Brown has not had the history of back ailments that (Johnson) has had." Brown, of course, has missed much of the last two seasons to injury and there are questions as to how effective he ever will be again.

There are no questions about Randy Johnson anymore, other than how many Cy Young Awards he will win before he just gets bored. No pitcher since ol' Cy himself has stayed this dominant for the second half of his 30s. It makes you wonder just what the first half of his 40s might have in store.

Alan Schwarz is the Senior Writer of Baseball America magazine and a regular contributor to ESPN.com.