The Black Cats have seen nine senior players depart over the course of the summer but have thus far secured just three new signings.
Alex Pritchard, Corry Evans and Callum Doyle have all joined the club – but head coach Lee Johnson is keen to see his numbers bolstered in the coming weeks.
It’s understood that Sunderland are close to completing a deal for Liverpool full-back Tony Gallacher, although Johnson wouldn’t be drawn on those reports following the 0-0 draw at Tranmere.
He did, however, admit that the club remain ‘in the mix’ for some key targets and told supporters to ‘watch this space’ when it came to incomings.
"I've seen the media reports, we know of him [Gallacher]," he said.
"He's a player on a list of ten or twelve options.
"We always want two for every position, and the plan is always to go in with probably 20 senior players and maybe four of the better younger ones to supplement that.
"It's a long season and we saw how much those injuries affected us.
"We're in the market, and we'll see what happens.
"Sometimes these things can take a week, two weeks, sometimes they drop in a day.
"We're certainly in the mix for a few and depending on what has happened behind the scenes today, we'll see.
"Watch this space."
So who could be next to arrive at the Stadium of Light? We take a look.