Tejada was invited to spring training with the Mets in 2010. He was the youngest position player on the Mets Opening Day roster since Tim Foli in 1971. On April 7, 2010 he made his major league debut and went 0-for-2 with a HBP in 3 Plate Appearances. On April 9, 2010 he recorded his first major league hit off the Washington Nationals' Tyler Walker. On June 4, 2010 the Mets re-called Tejada to replace Luis Castillo. With the activation of Luis Castillo from the DL on July 19, 2010, the Mets optioned Tejada to the Triple-A Buffalo Bisons. He was re-called on August 7, after Alex Cora was released and Jesús Feliciano was demoted to Triple A Buffalo Bisons. On September 5, 2010 in the seventh inning Tejada hit his first major league home run off Cubs pitcher Marcos Mateo on the first pitch. For the season, he batted.213/.305/.282.
2011
On May 17, 2011 Tejada was called up to play second base, thus moving Justin Turner to third base for the injured David Wright. He ended the season with a.284 batting average in 328 at-bats.
2012
Once Jose Reyes signed with the Miami Marlins, Rubén Tejada became the New York Mets starting shortstop for the 2012 season. On August 1, 2012, Tejada hit his second home run in the majors against Matt Cain of the Giants, his first home run since September 5, 2010.
2013
Tejada was placed on the 15-day disabled list with a strained right quad and called up shortstop Omar Quintanilla from the Mets triple-A affiliate Las Vegas 51s to take his spot on the roster. After Quintanilla's unexpected performance however, the Mets optioned Tejada to Las Vegas. For the season, he batted.202/.259/.260.
2015
Tejada suffered a broken right fibula in the second game of the 2015 NLDS vs the Dodgers as a result of Chase Utley sliding into him while attempting to turn a double play.
2016
On March 15, 2016, the Mets placed Tejada on waivers, and released him the next day after clearing waviers.
St. Louis Cardinals
On March 19, 2016, Tejada signed a one-year contract worth $1.5 million with the St. Louis Cardinals. Expected to fill in for the injured Jhonny Peralta at shortstop, Tejada himself injured his quad in the final game before the season, landing on the disabled list to begin the season. Tejada was activated on April 18, but the opening at shortstop was no longer there, having been filled instead by Aledmys Díaz. Tejada made his first major league appearance as a pitcher on May 20 in the ninth inning at Busch Stadium against the Arizona Diamondbacks, pitching one complete inning while allowing two earned runs, on back-to-back home runs to Chris Herrmann and Brandon Drury. The Cardinals designated Tejada for assignment on May 28. He had six hits in 34 at bats. Tejada declined the outright assignment, becoming a free agent.
San Francisco Giants
On June 13, Tejada signed a minor league contract with the San Francisco Giants. On June 29, Tejada was called up and started at third base after Matt Duffy was put on the 15-day disabled list. On July 20, he was designated for assignment by San Francisco. For the season, he batted.156/.270/.250 with the Giants in 32 at bats.
On December 12, 2016, Tejada signed a minor league contract with the New York Yankees. On March 27, 2017, Tejada was reassigned to Minor League camp.
Baltimore Orioles
The Baltimore Orioles acquired Tejada from the New York Yankees for cash considerations on June 4, 2017. He was assigned to the Triple-A Norfolk Tides. His contract was selected by the Orioles two days later on June 6. Tejada made his Orioles debut the next night against the Pittsburgh Pirates replacing an injured Manny Machado. For the season he batted.230/.293/.283 with the Orioles. On November 28, 2017, Tejada signed a minor league contract with the Orioles. He elected free agency on November 3, 2018.
Return to Mets
On March 23, 2019, Tejada signed a minor league contract to return to the Mets and was assigned to Triple-A Syracuse. He hit for the cycle on June 19, 2019 against the Charlotte Knights. On August 14, the Mets selected Tejada's contract. On August 22, Tejada was designated for assignment. He re-signed on a minor league deal on September 1. He became a free agent following the 2019 season.
Toronto Blue Jays
On January 17, 2020, Tejada signed a minor league deal with the Toronto Blue Jays.
