Born in Tovar, Mérida State, Venezuela, Santana was signed by the Houston Astros as a non-draft free agent in 1995. Selected by the Florida Marlins from Houston in the 1999 rule 5 draft, Santana was traded to the Twins. Finally, he made his debut in the 2000 season.

Santana is tough on both righthanded and lefthanded hitters. He works quickly and throws a 95 mph (153 km/h) fastball, a hard slider and a changeup. His pitches are too close to take, but difficult to drive, then batters find themselves lunging after balls that are down and out of the strike zone. He frequently rolls up double-digit strikeout totals, and many of his fans write his name with the middle initial "K" (the baseball scoring symbol for a strikeout) in place of his real middle initial.

A long reliever most of his career, in 2003 Santana took over a starting role after pitching in the bullpen nearly four months. He went 8-0 after August and pitched the ALDS opening game against the Yankees.

In 2004 Santana enjoyed one of the great second halves of modern times. His streak of dominance has been compared to Sandy Koufax and Nolan Ryan. He became the first pitcher since 1961 to give up four or fewer hits in ten straight starts, and his 13-0 record broke the old Major League second-half mark shared between Burt Hooton and Rick Sutcliffe.

It is interesting to compare that Santana's other second-half numbers, 11.13 strikeouts per nine innings, 1.21 ERA, 4.74 hits per nine innings, and 6.73 baserunners per nine innings, are mostly better than Bob Gibson's famous 1968 numbers (7.91 SO per 9 IP, 1.12 ERA, 5.84 hits per 9 IP, 7.77 baserunners per 9 IP). Beside this, Santana set a team season record with 265 strikeouts, surpassing the old 258 mark registered by Bert Blyleven in 1973.

Santana finished in good form with a 20-6 record, and lead the American League pitchers in strikeouts (265), ERA (2.61), strikeouts per 9 IP (10.46), WHIP (0.92), batting average allowed (.192), OBP (.249), SLG (.315) and OPS (.564), walking only 54 in 228 innings. Opponents stole only six bases in seven attempts against him, and his 20 victories ranked him second behind only Curt Schilling, who won 21 games for the Red Sox. He easily won the AL Cy Young Award over Schilling with all 28 first-place votes.

In the first inning of 2005, Santana struggled, giving up four runs, but he quickly regained his composure and returned to his Cy Young-winning form in an 8-4 victory over the Seattle Mariners. In his second game, he rocked the Chicago White Sox with 11 strikeouts as the Twins rolled to a 5-2 win. Following a brief slump in May 2005, Santana worked on improving his pitching form and was immediately rewarded with a seven-inning, two-run outing against the Toronto Blue Jays in which the Twins won 7-2. Santana finished with the second-lowest ERA in the American League, with an ERA of 2.87. Indians pitcher Kevin Millwood was the only pitcher with a lower ERA (2.86). He finished third in the Cy Young voting, finishing behind the winner, the Los Angeles Angels' Bartolo Colón, and the second place finisher, the Yankees' reliever Mariano Rivera.

--Wikipedia