Naysmith (groin) and Henderson (knee) will both be returning to full fitness in the next week or so and could come into contention for the game with Reading. But South Yorkshire's derby with Barnsley has come to quick for the duo. Meanwhile Brian Howard is ineligible to play.
Blackwell said: "Darius starts proper football training on Monday after completing his rehab and fitness schedules, whilst Gary should be fit for next week.
"With Brian Howard ineligible we shall go in with more or less the same squad as we did last week. We would normally be unchanged after a win if the lads have done well and would only consider a change if we were coming up against something special, like long throws."
In the Barnsley camp, Stephen Foster is suspended while new signing Simon Whaley comes into contention.