The on-loan Manchester United defender is still sidelined with the knee injury he suffered in the 1-0 win at Blackpool earlier this month, so left-back Chris Barker is set to deputise at the heart of defence once again.
There are even fears that Cathcart's season could be over, meaning he has played his last game for Argyle because of the injury.
Sturrock is also waiting on two unnamed players who have suffered knocks in the last week, but hopes to be able to name an unchanged side for the clash.
Belgian striker Emile Mpenza is back in training but seems unlikely to force his way back into Sturrock's in-form side.
Argyle are unbeaten in the last three matches and a win over Rovers could be enough to secure mathematical safety if other results go in their favour.
Doncaster defender Adam Lockwood will miss the long trip after being ruled out for the rest of the season with an ankle injury.
The centre-half was stretchered off in the 3-1 win at Ipswich and missed Easter Monday's 2-0 home defeat to Preston.
And scans have now shown he has suffered ruptured ligaments in the ankle and may yet need surgery on the injury.
Boss Sean O'Driscoll has no other new injury concerns, while James O'Connor, Brian Stock and James Coppinger have already been ruled out for the rest of the season.
O'Driscoll is unlikely to choose his side until the squad has made the trip to Devon as he side seek the point that will earn their Championship safety.
Sporting Life