Tampa moved 1 1/2 games in front of the New York Yankees in the division on Saturday, as Matt Joyce hit a two-run homer and B.J. Upton added two hits, including a solo shot, and two RBI, propelling the Rays to a 9-1 win.
Carl Crawford posted three hits and knocked in a run for the Rays, who have won four in a row and upped their lead in the East when New York fell to Boston on Saturday. Tampa is also a game up on the Minnesota Twinsin the race for the best overall record in the American League.
Ben Zobrist, Dan Johnson and Reid Brignac also drove in a run each for Tampa, which shrunk its magic number to clinch a playoff berth to two. A win coupled with a Boston Red Sox loss on Sunday would guarantee the team a spot in the postseason for the second time in team history.
Matt Garza (15-9) worked seven frames for the win, scattering eight hits and one run while striking out five.
"We came out really upbeat for the game. We had a lot of energy about the whole group," Rays manager Joe Maddon said. "We know what we're after. It's fun to watch."
Franklin Gutierrez finished 2-for-4 and drove in the lone run for the Mariners, who have dropped three in a row and eight of their last 11.
Doug Fister (6-13) was charged in defeat for five hits and four runs with four strikeouts over six innings.
Getting the call for the Rays today will be right-hander James Shields, who is 13-13 with a 4.96 ERA. Shields absorbed the loss on Tuesday against the New York Yankees, who hit him for five runs and seven hits in 5 1/3 innings.
Shields has faced the Mariners eight times and is 3-2 against them with a 2.31 ERA.
"As far as my pitching against them, I'm going to go out there and do my thing," Shields said. "No matter what kind of numbers I've had in the past, it doesn't really matter. My job right now is to get right and get focused."
Seattle, meanwhile, will counter with lefty Luke French, who is 4-6 with a 4.23 ERA. French was defeated in Toronto on Tuesday, as he surrendered five runs and seven hits in seven innings.
This will be French's first-ever start against the Rays.
Tampa Bay swept a three-game set in Seattle from May 4-6 before taking two of three at home from the Mariners later in the month.