Posted by joshkvt on 12/17/2013 12:49:00 AM (view original):
Both moves have to involve the same two players at the same time, in both directions. If Smith had been called up at the same time de la Rosa was placed on the DL, you'd have been safe to demote Smith when you activated de la Rosa.
I'm not sure if that's entirely true, because I've been able to do the following with no penalty:
Day 1: player A gets a 30 day injury, placed on the 15-day DL, player X called up to replace him.
Day 15: player B gets a 30 day injury, placed on the 15-day DL, player Y called up to replace him
Day 31: player A recovered, removed from the DL, player Y demoted
Day 46: player B recovered, removed from the DL, player X demoted
As long as the player was called up at the same time as a DL placement, and is demoted at the same time as a DL removal, I think you're good. It doesn't have to match player for player. Otherwise, on day 31 I would have had to demote player X instead of player Y or face a demotion penalty.