Jose Reyes and not getting hit by pitches
The New York Mets have 17 games left to play this season, and if Jose Reyes plays in all of them, and more importantly, avoids getting hit by a single pitch, he'll probably break the record for most plate appearances in a season without getting hit by a pitch. Sandy Alomar had 739 PAs in 1971, without getting plunked, and Reyes is already up to 682. He just needs to average 3.4 plate appearance per game in the final 17 to break the record. That, and he needs to avoid getting hit by a pitch.
Unfortunately there's a chance that he'll break the record for most plate appearances without a plunk, but not break the record for most at-bats in a season without getting hit. Which is just going to be confusing whenever someone wants to look up the single season record for not getting plunked... because it can reasonably be defined either way, even though using plate appearances maked more sense. Alomar got had 689 at-bats in 1971, but Reyes is only 614. Reyes will need to average 4.5 at-bats per game for all 17 remaining games to reach that record, which will be somewhat more difficult than the plate appearances record.