In May, when starting third baseman Chad Tracy was placed on the disabled list, the D-backs first considered Minor League infielders Brian Barden and Augie Ojeda to fill in. But both Barden and Ojeda were injured at the time.
So, the call went to Double-A Mobile for Reynolds, who was hitting .306 at the time for the BayBears.
"I hadn't really seen him during the spring," D-backs manager Bob Melvin said. "I give [GM] Josh [Byrnes], [director of player development] A.J. Hinch and the baseball staff the credit for making the call on him."
When Reynolds joined the team in Denver, he was still working out some loose ends with his apartment and stuff back in Mobile, so he asked Arizona third-base coach Chip Hale whether he thought Reynolds would be going back to Double-A or Triple-A once Tracy came back.
"I didn't know how it all worked up here," Reynolds said. "There were some unfortunate injuries, and I got my chance. I just tried to make the most of it."
After a torrid start -- Reynolds picked up two hits and a pair of RBIs in his Major League debut, had three hits, including a homer, two nights later and then nine days after getting called up he went 5-for-5 against the Astros with a pair of home runs and four RBIs -- Reynolds wasn't going anywhere.
"Certainly since Mark got here, right away he was pretty quickly our most productive offensive player," Melvin said.
Reynolds wound up splitting time at third briefly when Tracy came back from his injury, but Tracy was hampered by a bad knee throughout the year and wound up back on the disabled list.
Meanwhile, Reynolds went on to hit .279 with 17 homers and 62 RBIs. Included in the total were two prodigious blasts, a 453-foot shot at Turner Field and a 451-footer at PETCO Park -- the longest homer to left field in that park's history.
"I definitely started out on fire and I was seeing a lot of fastballs," Reynolds said.
But after a .426 May, Reynolds slumped to .162 and .194, in the next two months, respectively.
"The book got out on me and I started seeing more breaking stuff and I hit the skids for a couple of months," Reynolds said. "But I was able to make some adjustments in August and September and turn it around."
Indeed he did, as he hit .342 in August and .300 in September.
Equally impressive has been Reynolds' play at third. A 16th-round choice in the 2004 First-Year Player Draft, Reynolds had trouble finding a position in his first three seasons in the Arizona system.
Reynolds has said his most natural position is second, but in the Minors he also played third, shortstop and some first base. Then, last year in the Arizona Fall League, he played mostly left field.
"He made so much progress last year as a prospect that there was a bit of a decision whether to start him at Double-A or Triple-A this year," Byrnes said. "We decided to have him go to Double-A, where he had finished up the year before, and prioritize third base. He got off to a good start down there and circumstances, injuries, led to us calling his name. The rest is history."
Reynolds, who played shortstop at the University of Virginia, has impressed Melvin with his prowess at third.
"His athleticism over there was surprising," Melvin said.
So was his early arrival.
"It was definitely a big surprise," Reynolds said of his promotion. "Coming as early as it did -- and for me to put up the numbers I did -- it's kind of been a magical season. I'm just hoping to keep riding it right on through the World Series."