My understanding is that OVR reflects the player's overall stats. OVR increases when you Level a player up. OVR also increases when you Rank a player up (or, add a star). The higher your OVR the better and you can increase it by Levelling or Ranking (adding stars). You get a bigger increase with Ranking (adding stars) than Levelling, something like +10 per Rank/Star vs. +1 or so per Level.
My understanding is that OVR reflects the player's overall stats. OVR increases when you Level a player up. OVR also increases when you Rank a player up (or, add a star). The higher your OVR the better and you can increase it by Levelling or Ranking (adding stars). You get a bigger increase with Ranking (adding stars) than Levelling, something like +10 per Rank/Star vs. +1 or so per Level.
I think ranking increases your OVR more with higher players (uncommon vs. rare vs. epic).