Oakland tabbed two other players on the first day of the Draft, taking left-hander Dillon Overton out of Oklahoma at No. 63 in the second round and Virginia Tech shortstop/third baseman Chad Pinder at No. 71 with their competitive balance pick.
Day 2 of the Draft continues with Rounds 3-10, streamed live on MLB.com on Friday, beginning with a preview show at 9:30 a.m. PT. And Rounds 11-40 will be streamed live on MLB.com on Saturday, starting at 10 a.m.
McKinney committed to Texas Christian University in November but is likely to forgo college plans in favor of beginning a career with the same club he grew up rooting for, despite living less than an hour from Rangers Ballpark in Arlington.
"My dream is to become a big league ballplayer, and hopefully I can start that dream soon," McKinney said by phone. "I know the college coaches would love to have me there, but I'm just going to try to achieve my dream of becoming a Major League baseball player.
"Obviously, growing up 45 minutes from the Texas Rangers, you can't really be too proud about being an A's fan without getting some heckling. I've always just liked the way the A's play. I'm just very glad I got picked by them."
For the first time in the Billy Beane era, the A's opted for a high-school player with their first pick in back-to-back years, having taken shortstop Addison Russell at No. 11 last June. Before that, the A's hadn't drafted a prep player in the first round since pitcher Jeremy Bonderman in 2001.
The A's are hoping their decision to stray from the college pool and pluck from the high-school level, before a rarity in the organization, shows Russell -- playing at Class A Stockton -- and McKinney just how committed they are to grooming them into impact players at the Major League level.
Not one position player on the A's current roster is homegrown, and only three pitchers (Sean Doolittle, Dan Straily, A.J. Griffin) were drafted by Oakland.
"I've always said that we take the best player on our board, regardless of class," A's scouting director Eric Kubota said. "Certainly there was a long stretch where we favored college players, but I never thought it was a conscious effort not to take high-school players. It's just that the way the board has fallen the last few years that it's worked out that way."
The left-handed McKinney, who stands 6-foot-1, led Plano West to the Class 5A semifinals this season, hitting .394 (39-for-99) with six home runs and 32 RBIs to go along with a .585 on-base percentage using a swing he says he models after Josh Hamilton. He also drew 36 walks in 130 plate appearances and struck out only six times.
"Hamilton just has a beautiful swing," he said. "I try to keep my swing as short and compact as it can be."
Primarily a center fielder, McKinney noted he feels comfortable in any outfield spot. The same goes for first base, though remaining in center would be his preference.
"I believe in my abilities to stay in center," he said. "I hope I can, but I just do whatever I can to help the team win."
"We think he has a chance to go out and play center field," Kubota said. "He'll probably have to rely some on instinct. He's not your pure athletic center fielder but very instinctive and, in a lot of ways, reminded us of Mark Kotsay.
"You can say his tools are more average than plus, but he makes up for that in the outfield with instincts and jumps and reads. He's a very instinctual player, and that's why we think he has a chance to play center field. It's hard not to like the way this kid plays. He plays the game with intensity and energy. He's just the kind of guy that people will enjoy watching."
Oakland's current center fielder, Coco Crisp, has a club option for 2014, with 2010 first-round Draft pick Michael Choice lingering in Triple-A Sacramento. Choice is expected to make his big league debut by 2014, while McKinney said he has no time frame in mind when it comes to getting to The Show.
He just knows he'll have finally seen "Moneyball" when that time arrives.
"I'm for sure going to watch it in the next few days, no doubt in my mind," he said.
At the very least, he's already spoken to the man who inspired the movie. It was A's general manager Billy Beane who called McKinney on Thursday night to inform him the club was about to select him.
"I was surprised I even got words out when I heard that he said his name," McKinney said. "I was just astonished that it was him.
"There were other teams that were more open about it and talked to me a lot more. I didn't know that they were this interested, but I'm happy they were -- very happy."
Jane Lee is a reporter for MLB.com. Read her blog, Major Lee-ague, and follow her on Twitter @JaneMLB. This story was not subject to the approval of Major League Baseball or its clubs.