Club officials contacted late Wednesday afternoon would not confirm the signing, however.
It is believed that the 28-year-old Silva will receive a four-year, $44 million pact to help improve a starting rotation that lacked starters that pitched deep into games last season.
Silva falls into the innings-eater category, averaging more than 190 innings during the past four seasons with the Twins. He made 33 starts in 2007 and pitched at least six innings in 24 of them, including a pair of complete games. Seattle had just six complete games as a staff last season, half of them by departed right-hander Jeff Weaver.
Silva has a 55-46 record in six MLB seasons and is 47-45 with a 4.46 ERA in 125 big-league starts. He has been successful against AL West teams, posting an overall 16-8 record with a 3.48 ERA. He is 5-1 against the Angels, 3-2 against the Athletics and 3-4 against the Rangers.
He also is 3-1 with a 3.18 ERA in four career starts at Safeco Field.
Exactly where the Mariners go from here remains questionable. General manager Bill Bavasi's goal going into the offseason was to add to two starting pitchers. Adding Silva to the mix would accomplish that mission as Seattle selected knuckleball specialist R.A. Dickey in the Rule 5 Draft during the Winter Meetings.
Dickey was selected as the Pacific Coast League Pitcher of the Year after compiling a 10-2 record from June 1 through the end of the season for the Triple-A Nashville Sounds.
With Silva aboard, it might enable the Mariners to back off on their efforts to acquire left-hander Erik Bedard from the Orioles and thereby allow Seattle to keep right fielder Adam Jones, among others, which is what it would take to acquire the hard-throwing lefty.
Jim Street is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.