The Mariners were still telling teams that they aren't yelling selling, as of today. But despite their surprisingly nice season, their slim postseason hopes are getting slimmer by the day. So they should expect to field calls of inquiry right up until the deadline.
Should they decide to sell, the key target for teams will be lefthanded pitcher Jarrod Washburn, who is 8-6 with a 2.71 ERA. The Mariners like Washburn very much, but he's a free agent after the year so he'd be a prime candidate for trade.
They nearly dealt Wasburn to the Yankees last year at the deadline, and almost again to the Twins after the deadline. But Washburn's excellent season and expiring contract mean he isn't likely to get through waivers again this year.