Here's a general rundown of Japanese imports. Ichiro came, saw, hit a lot of baseballs. But he is *Ichiro* and if the absolute best from Japan didn't do well it'd have been a shocker. Hideki Matsui was also supposed to be one of the best, and though it took him a year to warm up to American baseball, he's doing much better. Sasaki was great for a few years, but pitching usually works well until batters figure you out. Sasaki didn't bomb, but it has happened to others. And then of course, Kaz Matsui has been an absolute dud.
Johjima isn't Ichiro, nor is he Hideki, nor does he pitch. As it has been mentioned before, go with the sure thing in a decent lineup. Ramon Hernandez is your man.