durable, Tejada started one of the longest contemporary playing streaks while with Oakland and continued it after signing with Baltimore as a free agent after the 2003 season.
There aren't really any other serious contenders here, so I'll just mention one also-ran. Eddie Joost (1947-54) was an All-Star twice, and garnered some MVP votes five times. Not a high-average hitter, he had some power for a middle-infielder, hitting 13-23 HR for six consecutive seasons. In 1949 he scored 128 runs, which was second best in the AL.
The choice for the starter at this position might be the most obvious for this team so far. Hall-of-Famer Mickey Cochrane (1925-33) played all but his last four seasons for Philadelphia, hitting over .300 most of that time. He had only moderate power, hitting 15+ HR in three seasons. He scored 100+ runs four times, and regularly had an OBP over .400. He won one of his two MVP awards for the Athletics, though it wasn't one of his most impressive seasons statistically, as he hit .293 with 10 HR and 57 RBI. Compare that with 1932 when he hit 23 HR, 112 RBI, and 118 runs, or his 1929-31 seasons when he hit .331, .357, and .349 respectively.
Terry Steinbach (1986-96) also played most of his career for the Athletics franchise. A consistent hitter, he had moderate power except his final season in Oakland when he busted out for 35 HR and 100 RBI. He became a free agent afterwards and signed with the Twins where he played for three more years before retiring.
While these two were pretty easy choices, I did consider a few others. Cy Perkins (1915-30) had a long career with the Athletics, but he was only a full-time player in five seasons. 1921 was his best year, as he hit .288 with 12 HR and 73 RBI. Frankie Hayes (1933-42, 44-45) is a little- known four-time All-Star, including 1939 when he hit .283 with 20 HR and 83 RBI, and 1940 when he hit .308 with 16 HR and 70 RBI. And Gene Tenace (1969-76) played the first half of his career with the A’s, splitting his time between C and 1B, and slugging 20+ HRs in his four full seasons with the club.
The clear first choice for the all-time A's outfield is speed burner Rickey Henderson (1979-84, 89-93, 94-95, 98) . Often considered the best leadoff hitter in this history of the game, he was nonetheless traded around quite a lot and actually had four stints in Oakland. He was drafted