PHOENIX -- Mark Reynolds took a unique route to the big leagues, and that is one of the reasons the D-backs felt comfortable giving him some contractual security.

Reynolds officially signed his three-year contract extension with the D-backs on Thursday just prior to the team's game against the A's at Phoenix Municipal Stadium.

The deal, which will pay him a guaranteed $14.5 million through 2012, with a club option for 2013, was first reported Monday, but there were still a few contract language issues that had to be resolved.

In May 2007, Reynolds was playing for Double-A Mobile when third baseman Chad Tracy went down with a knee injury. Two other infielders ahead of Reynolds on the depth chart were injured, so he got the call. It was supposed to just be for a few weeks.

Instead, Reynolds, who was a 16th-round pick in the 2004 First-Year Player Draft, started hitting homers, and he has not looked back.

"I think Mark, his career path has been out of the ordinary," D-backs general manager Josh Byrnes said. "He got here because of injury and never gave up the job. He's a tough accountable player. He's focused on winning, so we think he'll continue to be that."

Reynolds will make $500,000 in 2010, $5 million in '11, $7.5 million in '12, and there is an $11 million club option for 2013 with a $500,000 buyout. Reynolds also gets a $1 million signing bonus, and the deal includes a limited no-trade clause.

"It's peace of mind, but I have to go out and play still and prove that I'm worth what the [D-backs] invested in me and I'm looking forward to it," Reynolds said.

The 26-year-old hit 44 homers last year and drove in 102 runs while hitting .260 and improving his defense at third base. He also set a Major League record for strikeouts with 223, surpassing his own record from the year before, when he fanned 208 times.

The deal buys out Reynolds' first two years of arbitration, and should the club exercise the option, his third year of arbitration eligibility would also be circumvented. The deal provides the D-backs with cost certainty and Reynolds with security.

"I could have taken my chances and gone year to year," Reynolds said referring to the arbitration process. "At least you know it's a guaranteed deal and I'm just blessed and thankful for what I've been able to do thus far in my career. Like I said, I've got to go out and play up to my expectations. Trust me -- the hardest critic on me is myself, and I'm just looking forward to many more years with the D-backs. Hopefully this is just a kicking-off point for future things."

As the negotiations went on during the spring, Reynolds described them as a "distraction," and the two sides had set a deadline of Opening Day to get a deal done.

"There's no secret it was wearing on me earlier in spring, and to be able to get it completed and signed is great," Reynolds said."

There was a point where Reynolds said he was not sure an agreement was going to be reached.

"Early on, probably a little bit," he said. "But we moved a little bit, they moved a little bit and we were able to kind of meet in the middle. I think it's a good deal for both sides, and I'm just looking forward to a good season coming up and winning some ballgames."

Reynolds' contract is the second multiyear deal the D-backs have agreed to this spring with a player prior to his years of arbitration eligibility. On March 3, Arizona finalized the inking of outfielder Justin Upton to a six-year, $51.25 million deal.

"Me and J-Up have known each other for a long time, and it looks like we'll be sticking together for a little longer," said Reynolds, who, like Upton, is from Virginia. "I think it gives our lineup some stability for years to go. I know J-Up is not going to let off the gas one bit. I know I'm not going to let off the gas. We're still going to dive after balls and throw our bodies around and play how we know how to play.

"I'm not going to change one bit. I'm still going to be the same old self, mess around the clubhouse and give guys hard times, and people are certainly going to give me hard times. This doesn't change one thing. It's basically just a relief off my shoulders and nothing else."