Can position eligibility change during the season in baseball?
Eligibility(ies) will not be taken away until we reset them in 2014 for the 2013 season. What you see now will NOT go away.
Any player who is not eligible at a position -- but expected to play there and start there in 2013 -- will have to gain the eligibility this year in 2013 by starting 7 GAMES there THIS season. Players will not move over until this happens -- they must earn it, even if they are scheduled to start there, or are starting there in spring training, it must be earned.
Pitchers must make 3 starts or appear in 8 RP outings to earn eligibility there (so if you're counting on Chapman as a SP, he will move to a P after 3 starts).
Awesome, thanks for the detail.