Saints trio closing in on return from injury ahead of Munster clash
and live on Freeview channel 276
Haywood and Graham have not played since the defeat at Saracens last month, while Sleightholme has been sidelined since the win against Exeter Chiefs on the weekend prior to that.
"Mike's good - he's available for selection," Dowson said.
"He's been on the much-talked-about return-to-play protocol with concussion so we wanted to make sure we looked after him.
"But he's come through that and he's flying around, talking an incredible amount during training so he seems to be better.
"Ollie is also good, he trained this morning.
"He's had a slightly longer return-to-play so they're being very cautious in the way he's reintroduced.
"He's done plenty of running, plenty of weights before he got into the contact element of it.
"Sam Graham's just trying to shake off a shoulder injury so he'll be there or thereabouts this week."