Schweinsteiger has to rest some time, and there are no easy games for him to do so coming up. Despite coming off, I expect he's knackered after the Wolfsburg game, he ran his legs off all match long and isn't young any more. Carrick has repeatedly had his best games against Arsenal, he knows how to play Wenger's sides, this would be an opportune moment to use that experience. Then Bastian can come back in for Everton, City etc.
As for Blind, I just have the uncomfortable feeling that Van Gaal has been waiting for an opportunity to start Jones, and will see Blind's mistakes against Wolfsburg as an excuse to do it now. Which would be a mistake in my opinion, because Blind has otherwise been excellent and is important to the way we play. If you're right and he's still an automatic starter I'll be very pleased.