For each team, slots were broken down in 32 starts per slot (for a total of 160 games). Pitchers were ordered by FIP, lowest to highest. They were then broken up into slots. Their FIPs were weighted by inning allotment and a weighted average was calculated for each slot.
Chris Tillman had an FIP of 3.99 over 11 starts, Zach Britton had an FIP of 4.00 over 28 starts, and Jeremy Guthrie had an FIP of 4.51 over 32 starts. For the purpose of this study, Tillman's 11 starts all counted for the Orioles slot 1 along with 21 of Britton's 28 starts. The remaining 7 starts were put into the slot 2 position with 25 of Jeremy Guthrie's starts. When a pitcher's starts are split between multiple slots, it is assumed that their FIP is equal for every inning thrown and that their IP are equal for every start.
The Phillies pitching staff was quite amazing.
Below is the NL East FIP by Slot Table.
The following graph is simply a predicted fWAR value using only FIP and IP as described in this post. It serves as an approximation of fWAR worth.
This graph shows even more clearly how remarkable the Phillies rotation was last season. Keep in mind here that Roy Oswalt's numbers are split evenly between the 4 and 5 slots.
Below is the NL East xWAR by Slot Table.