2016-07-13 : If you don't play the card, it will remain exiled.

2016-07-13 : Playing the card exiled with Stromkirk Occultist's second ability follows the normal rules for playing that card. You must pay its costs, and you must follow all applicable timing rules. For example, if the card is a creature card, you can cast that card by paying its mana cost only during your main phase while the stack is empty.

2016-07-13 : The card exiled by Stromkirk Occultist's second ability is exiled face up.

2016-07-13 : Unless an effect allows you to play additional lands that turn, you can play a land card exiled with Stromkirk Occultist's second ability only if you haven't played a land yet that turn.

2016-07-13 : You may pay alternative and additional costs for that card, such as emerge and escalate costs. If it has any mandatory additional costs, you must pay those.

2016-07-13 : You may play that card that turn even if Stromkirk Occultist is no longer on the battlefield or no longer under your control.