6. Julio Teheran (Atlanta Braves), 23
Ever since Teheran made his major league debut in 2011 all he has done was get better and in 2015, Teheran is the clear-cut number one starter on a young Braves rotation. Last season Teheran made his first All-Star Game in just his second full season in the bigs. He posted a 2.89 ERA which ranked 13th in the National League. His record does not speak to his performance last year as he was just one game over .500. He posted a 4.3 WAR and started 33 games for Atlanta.
Barring injury (just like every player), expect Teheran to have an ERA around 3.00. His strikeout rate steadily increased from 2013 so expect that to continue to rise. His record might diminish, as it seems like the Braves are more geared for opening their new stadium in 2016 rather than contending this season. At just 23 years old, Teheran has a lot of room to grow, and I believe he will only get better which is a scary thought for the NL East when Atlanta is ready to contend.