"We're taking a look at lots of different people in different positions and different systems."
Keeper Luke Daniels, a loan signing from West Brom, will join the club for Tuesday's friendly at Partick Thistle.
Trollope revealed he had been "very pleased" with the club's progress so far, particularly their 3-1 win at Morton on Saturday.
"We had spells in the first half where I thought we were excellent," he commented.
He added that the aerial dominance of new centre-back James Tunnicliffe had also impressed.
Rovers' pre-season will conclude with home games against Premier League sides West Brom and Stoke, with a friendly at Cheltenham in between the two.
Trollope told the BBC he was hopeful of making at least one more signing, but added that "nothing is imminent".
Source: BBC Sport
Source: BBC Sport