I really think Tazawa has what it takes to be a really good major league closer. Live fastball, excellent control. Let's look at his numbers the past two seasons:
2012: 44.0 ip, 37 h, 7 r, 7 er, 1 hr, 5 bb, 45 k
2013: 15.1 ip, 13 h, 5 r, 5 er, 2 hr, 3 bb, 19 k
TOT: 54 g, 59.1 ip, 50 h, 12 r, 12 er, 3 hr, 8 bb, 64 k, 1.82 era, 238 era+, 0.98 whip, 1.2 w/9, 9.7 k/9, throws 70% of his pitches for strikes
Those are TREMENDOUS numbers. He's just 27, makes peanuts, and won't become a free agent until 2017. This is the guy you want as your future closer.