Another signing came later, under the radar. But it's one that could have considerable value in the big picture for the D-backs.
Joe Saunders, a proven starter with a 2008 All-Star Game appearance on his resume from his Angels days, returned to manager Kirk Gibson's rotation with a one-year, $6 million deal after the D-backs had chosen not to offer him arbitration.
Saunders, coming off a solid season with the club, gives balance to the rotation from the left side with righty Josh Collmenter taking the No. 5 slot. The D-backs have to feel good about matchups throughout the rotation, even with the Giants and their stacked unit fronted by Tim Lincecum and Matt Cain.
"I've been part of some good rotations," Saunders said, "and this is definitely one of them."
A residual benefit of Saunders' return is the pressure it releases on Gibson to identify a fifth starter. There should be no reason to rush any of the club's superb young arms, notably 2011 third-overall Draft pick Trevor Bauer.
"This organization is very deep," Saunders said on Monday morning. "The pitching is stupid deep with all the young guys coming up."
Arizona's decision not to offer arbitration to Saunders surprised most people inside the game. The former Virginia Tech star, a first-round pick of the Angels in 2002, didn't find much interest in a marketplace that had been open for business for two months.
The lukewarm climate around Saunders, in his prime at 31, was curious. His 12-13 record in 33 starts was deceptive, given his 3.69 ERA in a hitter-friendly park and his career-high 212 innings. This is a guy who was 17-7 in 2008, 16-7 in 2009 and owns a 4.16 ERA in 161 career starts, never missing one with an injury.
"I thought I had a pretty decent year, but that two months of free agency I missed kills you," said Saunders, a Phoenix-area resident. "Teams that had money budgeted had already spent it by the time I was out there.
"It worked out. I signed a one-year deal. They're happy. I'm happy. I get to sleep in my own bed at night and play for a great organization with great guys in the clubhouse.
"We had a terrific year, and I think what they've done this offseason has made the club even better. They made a lot of additions and hardly any subtractions."
Premium pitching prospect Jarrod Parker was the biggest loss, going to the A's along with pitcher Ryan Cook and outfielder Collin Cowgill in the Cahill deal.
The presence of Bauer alongside lefties Tyler Skaggs and Patrick Corbin -- potential starters acquired with Saunders from the Angels in the Dan Haren swap in 2010 -- enabled the D-backs to bite the bullet and part with Parker. Wade Miley, another southpaw, and Charles Brewer also come highly regarded in the D-backs organization.
The D-backs have few identifiable weaknesses. The pitching is deep, the defense is top shelf, and they can score in bunches with emerging superstar Justin Upton at the wheel in an offense blending speed and power.
The right fielder is an excellent defender, and center fielder Chris Young is right there with Upton, not to mention Parra, a 2011 Gold Glove winner.
"Upton's realizing he's becoming a superstar," Saunders said. "He can do everything."
At 24, with four-plus seasons already under his D-backs belt, Upton with natural progress can make the Matt Kemp leap this season into territory few venture. He can do that by elevating his .289 batting average and 88 RBIs while continuing to drive the ball (31 homers, 39 doubles in 2011).
Paul Goldschmidt, a big man with huge power, figures to be comfortable at first after putting up an impressive .474 slugging mark in 48 games.
Catcher Miguel Montero managed to produce 86 RBIs with 18 homers in 493 at-bats, providing some left-handed muscle in support of Upton and Goldschmidt. Respected Henry Blanco is an ideal mentor and backup for Montero.
Table-setters Ryan Roberts and Aaron Hill also have the ability to drive the ball, and Young can be a force by making more consistent contact.
Stephen Drew is the X factor. Blessed with uncommon power (.442 career slugging mark) for his position to go with superior defense, he's coming back from right ankle surgery and will not be rushed after missing the last half of 2011.
Seasoned athletes Willie Bloomquist, John McDonald and Geoff Blum offer premium infield insurance. McDonald's glove is gold, and Bloomquist and Blum are rock solid.
Saunders loves what he sees and would like to be part of this beyond 2012. But he also grasps the elusive nature of security.
"I'm looking forward to this season," he said, "making the best of it and helping us win. If the Diamondbacks don't want me back, I'll be a full six-year free agent next winter. We'll see what happens."