Voges has missed more than two months with a calf injury while Robson has recovered from a hamstring problem.
However, fellow batsman Nick Gubbins will not return from a hamstring problem until early September.
Bowler James Fuller, who has not played since May, will miss the rest of the 2017 season following elbow surgery.
The 27-year-old, who featured for England Lions last winter, last appeared for his county in the One-Day Cup defeat by Kent in May.
Ryan Higgins' shoulder injury picked up while fielding against Glamorgan on Friday will rule him out for three weeks.
Paul Stirling, whose calf problem has restricted him to T20 cricket, is set to be available for the Championship match at The Oval, as reigning champions Middlesex look to move clear of the two relegation places in Division One.
Adam Voges and Sam Robson have both been declared fit for Middlesex's County Championship match with Surrey, which starts on 28 August.