Who will claim the Phils' final rotation spot?

7/21/15: Vincent Velasquez strikes out seven batters over six solid frames and earns his first Major League victory in the processThe 2016 rotation should improve by default. Eight pitchers no longer with the Phillies made 97 starts last season, and those eight pitchers had a combined 5.21 ERA.

Veterans Jeremy Hellickson (4.62 ERA in 27 starts) and Charlie Morton (4.81 ERA in 23 starts) seem like modest upgrades over veterans Aaron Harang (4.86 ERA in 29 starts) and Jerome Williams (6.13 ERA in 21 starts) in both performance and upside. And a full season of Aaron Nola (3.59 ERA in 13 starts) and Jerad Eickhoff (2.65 ERA in eight starts) should provide a boost, if they follow up encouraging…