"My wife began to feel labor pains on Tuesday .... or was it Monday?" he said. "Then our baby was born on Dec. 12, or ... Oh, man, I hope she isn't watching this. Whatever the date, it was a week ago today."
So, officially, that makes Baby Haren's birth date Dec. 11, three days before Dad put a sparkle into the eyes of Arizona manager Bob Melvin and all the fans who had wondered where the D-backs could go from an upstart 2007 National League West title.
Thanks to general manager Josh Byrnes' diligent pursuit of the pitcher he had "targeted from the first day of the offseason," Melvin and the D-backs faithful have a rotation topped by Brandon Webb, who won a Cy Young Award in 2006 and finished second in '07, and Haren, who started an All-Star Game in '07.
"I'll tell you what type of a pitcher he is," said Melvin, glancing to his right on the podium in place for the introduction. "The attitude of a baseball team is affected greatly by the starting pitcher. When Dan takes the mound, you feel you're going to win.
"We acquired the pitcher we had looked to acquire when the offseason started."
It was not easy -- a free-for-all brewed when Oakland GM Billy Beane decided to again bite the bullet and reload, with the Red Sox, Yankees, Reds and Indians all at the forefront.
And it did not come cheaply, leading Byrnes on Tuesday to publicly thank his player-development people for "enabling us to land someone like Dan."
Acquired for a package of six Minor Leaguers, players with low profiles but perhaps high ceilings, Haren was asked whether the sheer numbers are intimidating. This is the second time he has been dealt -- but on the first occasion, in December 2004, he was one of three going from St. Louis to Oakland for Mark Mulder.
"There were a lot of expectations then," said Haren, alluding to having been the key player acquired for a left-hander who had gone an imposing 72-32 in his last four seasons with the A's. "So I've lived through it once before.
"There are expectations, but I'm fully prepared. I started my throwing program a couple of weeks ago, and I've never felt better. I'm confident, and ready to get the season started."
Chances are, he would not have been quite as enthusiastic had the anticipated trade sent him elsewhere.
"New York or Boston would have been interesting places to play, but once I realized Arizona was one of the teams interested, that's what we hoped for," he said, including Jessica in that sentiment. "And when Billy called and I heard 'Arizona,' it was a relief."
A laid-back California dude with the uncomplicated perspective of someone who grew up as a genuine fan of the game, Haren's D-backs wish was two-fold.
There is the location, an area with which he is quite familiar after three Spring Trainings with the A's.
And there is the composition of the team, an increasingly youth-driven group with a light-hearted attitude that translates into enthusiasm on the field.
"Absolutely, that's the reason I'm so excited by this team," Haren said. "To give up all those prospects shows a commitment to win now, but it's exciting to know I'll have a chance to see them get better for at least three years."
The reference was to the remainder, including a 2010 option, of the contract he had signed in Oakland at the end of the 2005 season. The finances -- a young pitcher with Haren's resume for about $19 million the next three seasons -- is another reason the deal held so much appeal for Byrnes.
"His age, the contract ... there are so many things," the GM said. "So [as the offseason unfolded] we kept coming back to him as our prime target. We knew he was the kind of guy who could help us win games in October."
Coincidentally, Byrnes on Tuesday formally acknowledged the contract extension for his manager that also takes Melvin through 2010.
For that, Melvin was grateful.
"I've been in baseball 28 years, and I've never before had a three-year contract," he said.
For Haren and Webb at the head of the rotation that will also include Micah Owings, Doug Davis and -- everyone cross your fingers -- Randy Johnson, Melvin seemed even more grateful.
Addressing specifically the related departure of closer Jose Valverde, traded to Houston for payroll reasons, Melvin said, "I think our pitching is better, overall. We'll have guys in camp who'll be able to pitch the ninth inning for us. All in all, we'll be a better team for it."
Haren looked forward to the Spring Training mixer, to being able to get to know his new teammates. He is familiar with only one of them -- which, Melvin suggested facetiously, may not be a good thing.
"[Eric] Byrnes is the only one I've talked to," said Haren, referring to the hyper outfielder with whom he played on the 2005 A's. "He wants me to buy the house right next to his."
"No, not that one," said the manager.