Rovers have added Conor Grant on loan and signed striker Alfie May and goalkeeper Ian Lawlor.
And Ferguson says there will be no more incomings this month, despite speculation linking the club with numerous full backs.
“I’m happy,” Ferguson told the Doncaster Free Press.
“We’ve done really good business, really early.
“Conor and Alfie were the main ones.
“And then obviously the goalkeeping situation took care of itself really after Marko [Marosi] got injured.
“Anything else would be speculation because I’m not looking for any other players to bring in this month.
“I’m happy with what I’ve got.”
Rovers are currently without an out-and-out left back with Tyler Garratt out on loan, Cedric Evina transfer-listed and Aaron Taylor-Sinclair injured.
But Ferguson says he is happy with the options at his disposal.
Niall Mason has established himself as Rovers’ first choice for the left back role while Tommy Rowe has filled in on occasion.
Rowe has also featured as left wing back when Ferguson has opted for a three man defence.
“I’m all right with what I’ve got,” Ferguson said.
“I think Mason has been outstanding, he’s gone in there and been outstanding for us.
“I’ve got Tommy Rowe and Craig Alcock who could play there.
“When we’ve go with three centre halves, Tommy will play as a wing back.
“I think I’m ok with the positions I’ve got.
“Bringing in Ian the goalkeeper was not something we expected to do at this part of the season so that is more money the board has given me.
“I’ve got to be conscious of that and get one or two out, just because of numbers.
“I’m happy though because Mason has been fine.”
Ferguson revealed Garratt will remain on loan at National League side Eastleigh until the end of the season following a successful first month. The deal is not likely to be confirmed until the end of his initial spell.
“Tyler is really enjoying it there,” Ferguson said.
“He’s playing games, competitive games so I’m pleased he’ll be there until the end of the season.
“Then we’ll look at it. He needs a very good pre-season with us and hopefully he can kick on.”
Garratt is contracted to Rovers until the summer of 2019.
Fellow left back Taylor-Sinclair should be available at the end of February after recovering from knee ligament damage.