Argyle have lost their last six league games ahead of Sunday's home clash against Nottingham Forest.
Sturrock has recently sealed temporary deals for young Premier League defenders Shane Lowry from Aston Villa and James Chester from Manchester United to bolster Argyle's porous defence.
And he said: "I would not say that I'm finished in that department, if I feel that area of the team still has to be strengthened.
"The cause of the club is more important than the number of loan signings we have."
Argyle already have five players on loan.