The Mariners said the 2010 American League Cy Young Award winner will officially sign the pact during a Wednesday press conference.
The terms of the deal weren't announced, but Fox Sports reported it is worth a total of $175 million, making the 26-year-old right-hander the richest pitcher in MLB history.
Contract talks with the Mariners ace were held up last week when a physical exam revealed an unspecified "elbow issue" with the durable right-hander, but sources told the Seattle Times the injury wasn't seen as serious.
The seven-year veteran threw a perfect game last season while compiling a 13-9 record with a 3.06 ERA over 33 starts. He struck out 223 batters over 232 innings.
For his career, the five-time all-star has compiled a 98-76 record over 238 games -- all starts -- with a 3.22 ERA and 1,487 strikeouts.