Tigers shortstop Carlos Guillen has agreed to a four-year, $48 million extension to stay in Detroit through 2011, SI.com has learned.

Guillen, who batted .320 with 19 home runs and 85 RBIs in 2006 in helping the Tigers to their first American League pennant since 1984, was heading into the last year of his current deal. The extension will begin in 2008.

Guillen, 31, has hit .318, .320 and .320 the past three seasons and has expressed several times that he wanted to remain in Detroit. His best friend is Magglio Ordonez. Plus, the Tigers have become more attractive since becoming a contender. Guillen has had some knee problems in the past, but the Tigers felt he was too important a player to let get away.

Detroit acquired Guillen from Seattle in 2004. He has a .320 batting average with 44 homers and 205 RBIs with the Tigers.

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