I found the rules here, basically four conditions for an injury request
1) Has to be approved by the League
2) A pitcher gets replaced by a pitcher and position player by position player
3) Injured Player misses rest of series and the next one
4) Replacement player has to be an eligible postseason player as well (ie, last year Barney was ineligible because he was acquired in September)
http://www.espn.com/blog/new-york/mets/post/_/id/109921/full-primer-on-playoff-roster-eligibility See Part 4
Tulo has learned to not swear on camera since last week. Was about to say Osuna has balls of steel or something, then stops himself lol. "He's got.........uh what you need to be a close"