The duo are in contention for the accolade after helping Liverpool win all four of their fixtures during the period.
Salah opened the month with a brilliant counter-attacking goal away at Southampton before producing a stunning long-range strike against Chelsea, which is also on the shortlist for Goal of the Month.
The Egyptian then scored twice in the Reds' 5-0 win over Huddersfield Town to take his league tally for the season to 21 and put him top in the Golden Boot standings.
Henderson, meanwhile, has thrived in an advanced midfield role, scoring or assisting in three matches.