Injuries hamper Matthaus debut
Vaslui right-back Milanov has a thigh injury while Levski Sofia left back Veselin Minev is suffering from a bad back, the pair joining a list of absentees which already includes PSV Eindhoven defender Stanislav Manolev.
The game in Cardiff will mark former World Cup-winning captain Lothar Matthaus's debut as Bulgaria coach after he took over from Stanimir Stoilov last month.
The 49-year-old German faces an uphill task to revive Bulgaria's chances of reaching the finals after back-to-back defeats to England and Montenegro in their opening qualifiers.
"We have problems but still I believe that we can beat Wales," Matthaus told reporters. "We have plenty of options and we're able to react appropriately in this situation."
Wales, who also have a new coach with Brian Flynn replacing John Toshak on an interim basis, lost their opening Group G qualifier 1-0 to Montenegro.