Not certain what to make of it, but the hit charts for the Mariners at MLB.com show Adrian Beltre as having warning track power this year at Safeco Field. Acknowledging the inherent subjectivity of whether or not an 'f' is on the warning track or not, I found the following information interesting.
The team has 34 homers and 17 warning track fly balls (WTF) at home. Attributing all of Everett's home runs to LH batters, the ratios are 15:3 HR:WTF for LHs and 19:14 HR:WTF for RH batters. Beltre comes out 3:5, and Johjima 4:4. They account for 53% the warning track power on the team at home, but only 21% of the home run power.
I suppose this just demonstrates the obvious; right handed power hitters struggle at Safeco.