Dave has been one of our form players this year
The inclusion of Sitaleki Timani is the only change to the Waratahs' starting team for this Saturday's season finale against the Reds in Brisbane.
Timani replaces Wycliff Palu, who has been ruled out through injury.
The big lock will form a Southern Districts second row alongside Kane Douglas, with Dean Mumm moving to the blindside and Dave Dennis taking over at No.8.
"Dave has been one of our form players this year and we are very confident in his all round skill set," said coach Michael Foley.
"Having him play at No.8 is not new to us [he played there against the Stormers] and it allows us to pick Sita in the second row alongside Kane."
After an impressive performance last weekend, prop Paddy Ryan earns his second start of the season.
"Paddy's performance against the Brumbies was most pleasing for someone coming back from an extended injury and having played only two club games," said Foley.
"He is a young players who was progressing particularly well before injury and it's excellent to see him pick up where he left off."
With Sekope Kepu still unavailable due to a calf injury, Jeremy Tilse retains his place on the bench.
Waratahs: 15 Adam Ashley-Cooper, 14 Lachie Turner, 13 Rob Horne, 12 Berrick Barnes, 11 Drew Mitchell, 10 Bernard Foley, 9 Grayson Hart, 8 Dave Dennis, 7 Chris Alcock, 6 Dean Mumm, 5 Kane Douglas, 4 Sitaleki Timani, 3 Paddy Ryan, 2 Tatafu Polota-Nau, 1 Benn Robinson.
Replacements: 16 John Ulugia, 17 Jeremy Tilse, 18 Lopeti Timani, 19 Jono Jenkins, 20 Brendan McKibbin, 21 Tom Carter, 22 Tom Kingston.
Date: Saturday July 14
Venue: Suncorp Stadium, Brisbane
Kick-off: 19.40 (09.40 GMT)
Referee: Steve Walsh (Australia)
Assistant referees: Andrew Lees (Australia), Angus Gardner (Australia)
TMO: Steve Lesczcynski (Australia)