In addition, outfielder Brett Gardner will now begin focusing some energy on campaigning, as he is among the five finalists for the American League Final Vote and is hoping his first career All-Star nod.
"I'm thankful and honored to have been selected by the players to represent the New York Yankees in the 2015 All-Star Game, and I'm looking forward to having a great time in Cincinnati with Tex," Betances said.
"I also hope our fans get behind Brett Gardner in the online final vote. He's a big reason for the success we've had this year, and I believe he should be an All-Star."
Betances, 27, will bolster the relief choices available to AL manager Ned Yost. The second-time All-Star has compiled a 1.50 ERA with a 5-1 record in 37 appearances this season, recording seven saves and finishing 12 games.
In 42 innings, Betances has struck out 68 batters against 18 walks, permitting 18 hits and 10 runs (seven earned). He ranks fourth among MLB relievers with 14.57K/9.0IP this season (min. 25.0IP).
• Gardner named Final Vote candidate
"You can certainly make the argument that Dellin has been the best reliever in all of baseball over the last two years," Yankees manager Joe Girardi said. "I certainly don't take for granted having him at the back end of our bullpen. He's a difference-maker, and his All-Star selection is well-deserved."
Teixeira, 35, replaces the injured Miguel Cabrera on the roster and is enjoying his third All-Star selection. He leads the American League with 59 RBIs and ranks fifth with 20 home runs (second-most among AL first basemen, to Albert Pujols), batting .243 (64-for-263) with a .356 on-base percentage and a .532 slugging percentage (.889 OPS) in 76 games.
"I'm honored to make the All-Star team and represent the Yankees in Cincinnati," Teixeira said. "I also want to congratulate Dellin for his selection and wish Gardy good luck with the final vote."
Thanks to a healthy right wrist (and perhaps the gluten-free diet he discovered this past offseason), Teixeira has stroked 16 doubles and scored 37 runs. He is tied for fourth in the AL with 44 walks.
"When you see the type of first half he has had this season, you certainly realize how much we missed him the last two years," Girardi said. "He's a top-flight run producer, a force in the middle of our lineup and a Gold Glover at first base. I'm so pleased he's being recognized with another All-Star Game selection."
The Yankees had some close calls when Monday's results were announced. Girardi also had campaigned for designated hitter Alex Rodriguez, whose .902 OPS leads all AL designated hitters, and catcher Brian McCann, whose 13 homers are tied for the most among AL backstops.
Voting is open now at MLB.com to select the final player for each League's 34-man roster via the 2015 Esurance MLB All-Star Game Final Vote. Fans can cast their votes from a list of five players from each League until 4 p.m. ET on Friday.
During the Midsummer Classic in Cincinnati on Tuesday, July 14, fans can once again visit MLB.com to submit their choice for the Ted Williams Most Valuable Player Award presented by Chevrolet. Voting exclusively at MLB.com, online and via their mobile devices in the 2015 All-Star Game MVP Vote presented by Chevrolet, the fans' collective voice will represent 20 percent of the overall vote that determines the recipient of the Arch Ward Trophy.
MLB.TV Premium subscribers will be able to live stream the All-Star Game via MLB.TV through FOX's participating video providers. Access will be available across more than 400 supported MLB.TV platforms, including the award-winning MLB.com At Bat app. MLB.com will provide extensive online coverage of the All-Star Week festivities, including the 2015 Gillette Home Run Derby presented by Head & Shoulders, part of Gatorade All-Star Workout Day on Monday, July 13. The Derby will feature a new format with brackets and timed rounds and will be broadcast live by ESPN and MLB.com beginning at 8 p.m.
The 86th All-Star Game will be televised nationally by FOX Sports (7 p.m. air time, 8:15 first pitch), in Canada by Rogers Sportsnet and RDS, and worldwide by partners in more than 160 countries. ESPN Radio and ESPN Radio Deportes will provide exclusive national radio coverage of the All-Star Game. MLB Network and SiriusXM will also provide comprehensive All-Star Week coverage. For more information, please visit allstargame.com.