Red Sox slugger David Ortiz agreed Monday to a four-year contract extension through 2010, just five months after finishing runner-up for the AL MVP award. The designated hitter was in the last year of a $12.5 million, two-year extension he signed in May 2004. That deal called for a $6.5 million salary this year and gave Boston an option for 2007, currently valued at $8.4 million with a $1.4 million buyout. Ortiz's new deal contains a team option for 2011. "I want to finish my career as a Red Sox player," Ortiz said at a news conference at Fenway Park. "I'm going to be around for a while. I'm pretty sure New England is going to take this as good news."