Igarashi has not had much success at all in his first two years at the major league level with a 5.74 career ERA, 8.7 K/9, and 6.0 BB/9.
I'm really not sure why the Pirates made this move. It could be compensation for the loss of Jose Veras this week, but even without Veras the Pirates have a really solid bullpen with a bunch of arms that project better than Igarashi's. I wrote this piece about the Pirates bullpen just a few hours ago, so you can tell that I'm very confused with why the Pirates would make this move.
*edit
It looks they signed Igarashi to a minor league deal, which makes sense. Igarashi will get a spring training invitation. I guess this move doesn't hurt the team but I can't see it helping, so I don't get spending the money on him.
Photo courtesy of ESPN.com