Left-handed starting pitcher Gio Gonzalez and right-handed starting pitcher Tanner Roark
The Washington Nationals seem to be content with trading Tanner Roark or Gio Gonzalez this offseason. Gonzalez comes with two years of control while Roark has three years of team control. Gonzalez is 31-years old, while Roark is 30-years old.
Gio Gonzalez is the better of the two pitchers. In 1,442 career innings pitched Gonzalez owns a 3.73 ERA, 3.53 FIP, 3.70 xFIP, and a 24.4 WAR. Tanner Roark has pitched 573 1/3 innings pitched he owns a 3.01 ERA, 3.73 FIP, 3.96 xFIP, and a 7.1 WAR.
Personally, I prefer Gonzalez over Roark. Gonzalez has superior stuff, he is left-handed, and he has been a starting pitcher his entire career. Tanner Roark bounced between the National bullpen in both 2013 and 2015.
Neal Huntington has stated the Pirates would love to add a veteran starting pitcher this offseason. Both Gonzalez and Roark fit this bill. Additionally, both come with years of control.