DP/Flex...and ejection

[Andy]

Situation: Team A (visitor) submits a lineup with ten players using DP/Flex and no subs. Top of the first, two outs, R1 on second. R1 attempts to advance home on a hit ball to the outfield, throw comes in, catcher has ball, R1 makes no attempt to slide or avoid, but basically plows through catcher. I call R1 out and eject her. R1 is not the DP or Flex. Since the team was still able to put nine players in the field, but could only bat eight, we allowed the game to continue with an out each time R1's spot came around in the order. Several of us looked in the rule book, but could not come up with a definitive ruling (ASA). Let's hear what you all say - rule references if possible. Thanks