"Siddesh Lad has been injured and is being replaced by Manish Rao," informed Mumbai Cricket Association's joint secretary Nitin Dalal today.
Lad was their best batsman in the previous lost game against Karnataka.
Rao, who was in the squad for the previous game, had been dropped for the do-or-die match against Gujarat to include left-arm spinner Iqbal Abdullah.
The 40-time Ranji champions' qualifying hopes for the knock out rounds are hanging by a slender thread following their historic first-ever loss to Karnataka (by 160 runs) at Bangalore.
Mumbai are already without the services of several key players because they are either busy with India duty (Zaheer Khan, Ajinkya Rahane) or are injured (Abhishek Nayar, Dhawal Kulkarni).