By Wendy Thurm

OAKLAND, Calif. -- Sonny Gray may be the best pitcher you've never heard of.

With less than a full season of major league starts under his belt, the 24-year-old right-hander out of Smyrna, Tenn., and Vanderbilt University is the ace of the Oakland Athletics' starting rotation. Through seven starts this season, Gray is 4-1 with a 1.91 ERA. Hitters are batting only .223 off Gray when they make contact with his pitches. A lot of guys don't make contact at all. Gray has struck out 20.8 percent of the batters he's faced. He was the American League Pitcher of the Month in April.

This isn't the way the A's drew it up heading into spring training.

Gray was in their plans for the starting rotation, but Jarrod Parker was the A's expected ace. Then Parker suffered a torn ligament in his pitching elbow and underwent Tommy John surgery -- his second -- in late March. A.J. Griffin, another young right-hander, also complained of elbow soreness and eventually succumbed to the surgeon's knife for his own Tommy John procedure. That left the A's with Scott Kazmir, a free-agent who signed with the A's over the winter after resuscitating his career in Cleveland last season; Jesse Chavez, a journeyman reliever-turned-starter; Tommy Milone, an average left-handed starter; Dan Straily, an average right-handed starter with a little more than a season's worth of experience; and Gray.

A's manager Bob Melvin isn't surprised by Gray's early success. "It has a lot to do with his makeup. He's motivated, driven and not scared of anything," Melvin said before Wednesday's doubleheader against the Seattle Mariners. "Sonny is aggressive. He goes after guys. He's not afraid to shake off the catcher. Some young guys are. Sonny is not." For Melvin, the difference between young pitchers who do well from the start and those who struggle is confidence. "The young guys who do well -- they're fearless. They embrace the challenge of pitching in difficult venues and against difficult lineups," said Melvin.

Gray toys with batters using a combination of his two-seam fastball, four-seam fastball, changeup and curve. The fastball sets up everything. "I feel good with the fastball," Gray told me Wednesday morning. "It has speed with movement down in the zone. I use it to get as many groundballs as possible." The stats bear this out. Through Wednesday's games, Gray had the 11th-best groundball rate among all qualified starters, at 55.6 percent. He's allowed only two home runs.

The numbers show a startling similarity with another pitcher who started his career with the A's, but now pitches across the bay in San Francisco. Tim Hudson has the ninth-highest groundball rate this season, at 58.9 percent, just a tick above his career average. Bob Melvin says it's not just the numbers that draw comparisons between Gray and Hudson.

"With Hudson, the pitch is going down or to the right," Melvin said, referring to Hudson's slider. "Sonny's fastball goes in all different directions. It's pretty unique in what his fastball does." But if you want to compare Gray to another pitcher, "Hudson is a good place to start."

What does Gray make of the comparison to Hudson? "People stay stuff all the time about the history of young pitching studs here in Oakland," he said. "But I take it one day at a time."

Melvin also mentioned Tim Lincecum, when I asked about the slight decline in Gray's fastball velocity. In 2013, Gray averaged 92.4 mph on his two-seamer and 93.2 mph on his four-seam fastball, according to PITCHf/x. This season, those numbers have dropped to 92.1 and 92.7, respectively. "That's pretty consistent with what you see out of a young starter throwing in the mid 90s. Once he's in a regular five-day rotation, you'll see the velocity go down a bit," Melvin said. But, he added, Gray sometimes saves velocity for his four-seamer, especially later in the game, with two strikes.

It looks something like this:

gray_whiff_castro

Gray's darting, diving fastballs are the foundation, but don't sleep on his wicked, body-bending curve. It can make a fool out of the most experienced vets, who have no idea what's coming. Here's Gray psyching out Texas Rangers third baseman Adrian Beltre in a late-April game.

And then there's the changeup. With two strikes, Gray might rear back for his velocity pitch, but just as often he'll go to his changeup, with speeds ranging from the low-to-mid 80s. He teases the batter with what looks like a hittable pitch, but looks like can deceiving.

Gray takes the mound again on Saturday at home against the Washington Nationals in the A's first interleague series of the season. He's not the least bit concerned about facing a lineup of batters he knows nothing about. "I don't know much about them, but they don't know me either," Gray said. "You just go with your strengths and try to execute what you've done all year."

One pitch at a time. One game at a time. It's a formula not only for Gray's success, but for his teammates as well. Be fearless, and if you fail, come back stronger the next time. Melvin likes the word resilient to describe his squad.

Gray chose the word fun. "I love it here," he told me. "The coaches are awesome. And the young guys are fun to play with and be around. I want to be in Oakland for a really long time."

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Wendy Thurm is a contributing writer at FanGraphs and Bay Area Sports Guy. She has also written for ESPN.com, SBNation, The Score, and the Wall Street Journal. You can follow her on Twitter @hangingsliders.