Franklin is 3-12 with a 5.04 ERA. The veteran right-hander has lost eight straight decisions, with his last win coming against the Chicago White Sox on June 5.
Only Kansas City starter Darrell May has more losses in the AL with 14.
Franklin pitched well enough to win his last start Wednesday against Kansas City, allowing three runs and five hits over eight innings in a 3-2 loss.
Mariners hitters had a hard time solving Devil Rays rookie Scott Kazmir in a 9-0 loss to Tampa Bay on Monday.
Seattle outfielder Ichiro Suzuki went 1-for-4 with a single, his major league-leading 198th hit of the season. Suzuki is hitting .517 (15-for-29) over the last seven games to raise his average to a major league-best .369.
“I’ve never seen anybody this hot for an extended period of time,” Mariners manager Bob Melvin said.
Suzuki was one of the few Mariners hitters to have success against Kazmir. Considered one of the top pitching prospects in baseball, the 20-year-old left-hander gave up four hits and struck out four in five innings in his major league debut.
The Devil Rays ended a six-game road losing streak and won for only the second time in their last 17 away from home.
Tampa Bay manager Lou Piniella improved his record to 12-11 against the Mariners, the team he managed for 10 seasons before asking out of his contract to return to his hometown after the 2002 season.
Devil Rays slugger Aubrey huff sat out the game with back spasms. Huff, who is listed as day-to-day, leads the team with 22 homers and 80 RBIs.