The Mariners, mired in a 12-game losing streak with the worst offense in baseball, aren’t in a position to declare that vast numbers of their players are “untouchable.”

Indeed, many rival executives believe only three players are off limits as the July 31 non-waiver trade deadline approaches: right-handed starters Felix Hernandez and Michael Pineda and stud rookie Dustin Ackley.

While it’s a no-brainer that general manager Jack Zduriencik will listen to offers for impending free agents like Jack Wilson, Adam Kennedy, and Jamey Wright, the greater intrigue surrounds three pitchers who are under club control for next year: closer Brandon League, left-handed starter Jason Vargas and right-handed starter Doug Fister.

Zduriencik isn’t under pressure to move any of them, since each will remain relatively affordable in 2012. League is particularly valuable, since, even at a raise from this year’s $2.25 million salary, he’ll be a reasonably priced closer next year. However, the team’s anemic offense over the past two years could compel the GM to seek pitching-for-hitting trades.

Of the group, the 27-year-old League is the closest to free agency. Next year is his final season of salary arbitration. Vargas, 28, is on track to become a free agent after the 2013 season. Fister, 27, isn’t scheduled to become a free agent until 2015.

Because Vargas is closer to free agency than Fister, sources say Zduriencik would be more likely to move the lefty. More than a half-dozen scouts watched each pitcher start for the Mariners in Toronto this week; Fister fared better than Vargas with the evaluators on hand.

The Reds appear to be an ideal trade partner for the Mariners if they decide to move Fister, Vargas, and/or League. The Reds would like to upgrade their rotation and bullpen and have a number of intriguing hitters at the upper levels of their farm system.

The Tigers have been among the most aggressive clubs in scouting starters this month. At present, they don’t have a veteran left-hander in their rotation.

— Jon Paul Morosi and Ken Rosenthal