The combative Dowson joins Red Rose captain Chris Robshaw, Scarlets rookie Ben Morgan and Leicester's Tom Croft as the only back-rowers left in the squad.
And with Robshaw already confirmed as captain and Croft a near certainty to start on the blindside it appears to be a straight shootout between Morgan and Dowson for the final back-row berth.
In the backline the uncapped Saracens pair of Brad Barritt and Owen Farrell look to have nailed down the starting centre positions while clubmate Charlie Hodgson will start at fly-half.
That leaves the uncapped Jordan Turner-Hall to take a place on what could be a very much untested international bench including Wasps hooker Rob Webber and Saints scrum-half Lee Dickson.
Tom Palmer, Mouritz Botha and debutant Geoff Parling are the only locks retained in the squad meaning that the two players missing out on the 22 will in all likelihood come from the front-row and the back three.
Either Matt Stevens or Joe Marler could be the prop to be cut when the squad is announced while in the back line David Strettle, Charlie Sharples and Mike Brown are all vying for a solitary back-three spot alongside established stars Chris Ashton and Ben Foden, with a further spot available on the bench.
The Bath quartet of Dave Attwood, David Wilson, Lee Mears and Matt Banahan have all been released back to their club for the weekend action along with Alex Goode, Thomas Waldrom, Calum Clark and Joe Simpson.
Mouritz Botha (Saracens)
Alex Corbisiero (London Irish)
Dan Cole (Leicester Tigers)
Tom Croft (Leicester Tigers)
Phil Dowson (Northampton Saints)
Dylan Hartley (Northampton Saints)
Joe Marler (Harlequins)
Ben Morgan (Scarlets)
Tom Palmer (Stade Francais)
Geoff Parling (Leicester Tigers)
Chris Robshaw (Harlequins)
Matt Stevens (Saracens)
Rob Webber (London Wasps)
Chris Ashton (Northampton Saints)
Brad Barritt (Saracens)
Mike Brown (Harlequins)
Lee Dickson (Northampton Saints)
Owen Farrell (Saracens)
Ben Foden (Northampton Saints)
Charlie Hodgson (Saracens)
Charlie Sharples (Gloucester Rugby)
David Strettle (Saracens)
Jordan Turner-Hall (Harlequins)
Ben Youngs (Leicester Tigers)
The following players will return to their Aviva Premiership clubs this evening and be available for the weekend's LV= Cup Round 4 matches:
Dave Attwood (Bath Rugby)
Matt Banahan (Bath Rugby)
Calum Clark (Northampton Saints)
Alex Goode (Saracens)
Lee Mears (Bath Rugby)
Joe Simpson (London Wasps)
Thomas Waldrom (Leicester Tigers)
David Wilson (Bath Rugby)