Heaslip joins fellow Ireland forwards Leo Cullen, Cian Healy, Bernard Jackman, Shane Jennings, Kevin McLaughlin and Malcolm O'Kelly in the squad which also includes promising flanker Rhys Ruddock.
Ruddock is joined by his fellow Ireland Under-20 colleague Andrew Conway who is named amongst an array of backs which includes the experience of Gordon D'Arcy, Shane Horgan and Eoin Reddan as well as Fergus McFadden and Eoin O'Malley who have both been in good recent form.
Leinster coach Michael Cheika will confirm the team and replacements on Thursday afternoon.
Commenting on the squad's current injury concerns, Cheika said: "Johnny (Sexton), as has been reported, had a little operation. We will just see how he pans out.
"I would say, looking into the extent of the injury first hand, that it is probably going to be a few weeks - It's a little crack in his jaw.
"He is pretty good really, but it is a pretty obvious injury and he can't just go out there and say, 'I'll be alright', strap it up and away you go.
"I would say it is fairly touch and go as to whether he plays in the Heineken Cup semi-final (against Toulouse) or not. Our first concern is this week's match but he is definitely out of that one. (Rob) Kearney is pretty much the same.
"Rob, with his ankle, is not as bad as we first thought. When you get carried off on a stretcher it isn't ideal but, again, he will be touch and go in that environment and he is definitely out of this week's match.
"(Brian) O'Driscoll is out of this week's match as well. We are probably a little bit more hopeful for him now (with his knee injury), of getting himself right in the next couple of weeks."
On the challenge of facing the Ospreys this Friday, the Australian added: "We have to play a team that should probably be in the Heineken Cup semi-finals themselves and they will be hurting from it.
"Hopefully Ulster can rough them up a little bit tomorrow night and get them as tired as humanly possible for Friday!
"We believe in ourselves, there is no issue there. We have got to manage our resources well and we have had a good season so far. We haven't had many losses.
"The focus has got to be on ourselves. Maybe because we hadn't played Clermont Auvergne before I was a bit guilty of making the team too aware of the opposition's threats as opposed to worrying about Leinster, so that's a lesson learned for me.
"I'll just get the team sorted out in its own play. We have worked on a lot of basic play now that we are going to stick to over the next while - get everyone positive about our own attack and defence."
LEINSTER Squad (v Ospreys) - Backs (11): Shaun Berne, Andrew Conway, Gordon D'Arcy, Girvan Dempsey, Shane Horgan, Simon Keogh, Fergus McFadden, Isa Nacewa, Paul O'Donohoe, Eoin O'Malley, Eoin Reddan.
Forwards (16): Leo Cullen, John Fogarty, Cian Healy, Jamie Heaslip, Nathan Hines, Bernard Jackman, Shane Jennings, Stephen Keogh, Kevin McLaughlin, Malcolm O'Kelly, Mike Ross, Rhys Ruddock, Richardt Strauss, Devin Toner, CJ van der Linde, Stan Wright.