short of contacting support, or someone else giving advice, i'm at a loss why the offer extension doesn't show up for you. The on-line manual says this:
"Signing Extensions
You can attempt to extend the contracts of players already under contract, to avoid losing them to free agency. Most players prefer to negotiate extensions only in the final year of their current contracts. However, this is not necessarily always the case. To offer an extension to a player currently under contract, open his
Player Profile and select
Offer Extension from the Action menu. Alternatively, right-click on the player's name and select
Offer Extension from the right-click menu."
of course, you must have money available to offer extensions.
i've contacted support a couple of times, over really minor issues, and they've been very quick and helpful. i think the email is:
support@ootpdevelopments.com
i only play the game in sim mode, so don't know how you could schedule a spot starter for a double header, unless in your pitching staff tab you designated someone as an emergency starter, but that's just a guess.
sorry wasn't more of a help.