Tejada developed quickly into a top-notch prospect, showing early signs of power. He reached the majors towards the end of the 1997 season, joining a struggling Oakland Athletics club. Though he only hit .202 in 26 games that year, the A's saw potential in the 21-year-old Tejada and gave him the starting shortstop job beginning in 1998.
The A's, and Tejada, steadily improved over the next two years. His hitting improved as he gained more discipline at the plate. In 1998, he hit .233 with 11
home runs and in 1999 his average jumped to .251 with 21 home runs.
After a solid 87-win campaign in 1999, Tejada and a core of young players led their A's to their first
American League Western Division title in eight years in 2000. Bolstered by an
American League MVP-winning performance by
first baseman Jason Giambi, and aided by Tejada's .275 average and 30 home runs, the A's won 91 games. The A's faced the
New York Yankees in the first round of the postseason, which was won by the Yankees 3-2 in Oakland. The Yankees would go on to win the
World Series that year, their fourth championship in five years.
In 2001, Tejada had a comparable offensive year, hitting .267 with 31 homers. The A's captured the American League
wild card with a 102-60 record. In the postseason, however, the A's fell to the Yankees in five games, blowing an initial 2-0 series lead.
Tejada's breakout year came in 2002. With the departure of Jason Giambi to the New York Yankees during the offseason, and a leg injury to slugger
Jermaine Dye, the A's lost two of their key offensive players. Tejada hit .308 with 34 homers and led the A's to their second Western Division title in three years. Their campaign included an American League record 20 game win-streak. Tejada contributed one-out, game-winning hits in the 18th and 19th games of that run: a three-run homer off
Minnesota Twins closer
Eddie Guardado for a 7-5 victory and a bases-loaded single against
Kansas City Royals reliever
Jason Grimsley to break a 6-6 tie. Tejada also showed modest speed on the basepaths with 18 steals over a two-year stretch. His performance was rewarded with the 2002 American League MVP award. For the third straight year, though, the A's fell in the fifth game of the ALDS, this time to the
Minnesota Twins.
The next year, both the A's and Tejada got off to a slow start, with the shortstop hitting under
.200 for the first month of the season. Improved play in the second half of the season led the A's to their second straight Western Division title and their third in four years. Tejada hit .278 with 27 homers for the year, a decrease from his numbers in 2002, but still leading many offensive categories for shortstops.
In a tension-filled series, the powerful offense of the
Boston Red Sox narrowly edged out the A's in the first round, once again in five games. Tejada was known for his public display of anger toward Boston starting pitcher
Derek Lowe at the series' conclusion for what he perceived as obscene gestures. Lowe denied the accusation, claiming his fist pump was in celebration only.
By the end of the 2003 season, Tejada had established himself as one of baseball's premier shortstops. The A's elected not to resign the free agent, citing budget concerns and a young
Bobby Crosby coming through the system, so Tejada signed a six-year, $72 million deal with the Baltimore Orioles during the offseason.