RANKX Player Position Rank over Time

Farily new with DAX and struggling with filtered RANKX. I have a StatsDB table and a playerkey table for a fantasy football database I'm working on.

Each row of the data table is a game log for a player:

StatsDB:

• PlayerID (relation)
• Year
• Name
• Position
• Team
• Week
• Pass Attempts
• Pass Completions
• etc. - Other relevant offense statistics. 

PlayerKey

• PlayerID (relation)
• Player Name
• Current Position

I created measures that calculate fantasy points based on stats. 

Example Measures:

• FPTS Rush Yds:=CALCULATE(sum([Rush Yards])*.1)
• FPTS Total:=[FPTS Fumb Lost]+[FPTS Rush Yds]+[FPTS Pass TDs]+ etc.

I have a points rank that seems to work for the context of the pivot / slicers - 

• FPTS Rank:=if(not(ISBLANK([FPTS Total])),rankx(filter(all(PlayerKey),not(isblank([FPTS Total]))),[FPTS Total]),blank())

However, my goal is to have a "fantasy points positional rank" measure. Where did a player rank in fantasy points scored at his position over any given period of time?

Any ideas how to go about this? Would be much appreciated! I can do this manually but am trying to work positional ranks into the data model and am stuck.