Adam Rubin is reporting that Mets top pitching prospect Zack Wheeler will be promoted to Triple-A Buffalo on Sunday.

Wheeler will get one final start for BInghamton tonight against Harrisburg, the Nationals' Double-A affiliate, and he will then make his International League debut against Washington's Triple-A Syracuse affiliate.

The 22-year-old has posted a 9-6 record along with a 3.29 ERA for the B-Mets in 2012. He allowed 88 hits and 39 walks and hit 11 batters while striking out 106 in 109 1/3 innings. He is third in the Eastern League in opponent average (.227) as well as K/9 (8.73), and he leads the circuit in HR/9 (.08) with just one allowed all year.

Unfortunately, Wheeler just struggled through his toughest month of the season, posting a 5.25 ERA in July. If you look closely, however, the reason for his promotion is clear.

April BB/9: 4.91

May BB/9: 2.33

June BB/9: 3.86

July BB/9: 1.50

Despite the slight spike in June, Wheeler has been focusing on limiting walks. For more on Wheeler, take a look back at what we had to say in our Pre-season Top 50 Rankings.