I HATE minimum requirements. EA can release whoever they want, but we can't.
But, you CAN have just 8, offensive linemen as long as you have two centers (if EA already has two centers.... actually, you can have 7 if you move your long snapper to center).
You can have two guards on one side and one on the other. Same with tackles.
If you have two on each side, change a player currently on the team from another position to the opposite side of the lineman you want to release. Then, release the player. Now, change the player you changed initially back to their original position. You won't get the "minimum requirement" message if you do it this way.