Sunderland will be hoping to build on what has been a successful first campaign back in the Championship.

They will give themselves the best chance of doing this by enjoying a productive summer transfer window, with the Black Cats clearly lacking depth in some areas.

Their central defence could potentially benefit from another addition or two – and it’s clear that they need to rebuild their forward department.

Although they managed to recruit Joe Gelhardt in January, they needed at least one or two more strikers to arrive during the winter and their failure to fully address this department was a real disappointment.

Thankfully for them, they have the opportunity to make amends when the upcoming window opens and the Wearside outfit may already have targets lined up, although uncertainty may be disrupting their plans.

It’s unclear whether they will be in the Premier League or the second tier next season – and which targets they pursue may depend on which division they find themselves in.

But there are some players they should be looking to recruit regardless of whether they are promoted or not – and we take a look at four free agents that could be suitable for Mowbray’s side.

Free agents Sunderland should target

Joel Robles

Signing a one-year contract at Leeds United last year, his deal expires this summer, and you feel he could be a good addition at the Stadium of Light.

The 32-year-old has more experience at a higher level than Alex Bass – and this added competition could help to take Anthony Patterson’s game to the next level.

His wage demands could potentially be a problem – but the Black Cats can probably afford to spend a decent amount on his salary considering they would be recruiting him for free.

A one-year deal should be handed out, so Mowbray can assess the stopper before deciding whether it would be a good idea to extend his stay beyond 2024.

Daniel Ayala

This may seem like a bonkers signing considering his injury record – but the central defender has a decent amount of experience under his belt and could be a good squad option.

Mowbray has worked with Ayala before and with this in mind, it shouldn’t take too long for the current Blackburn Rovers man to adapt to life on Wearside.

Their lack of options in central defence against West Bromwich Albion last weekend and Watford yesterday reinforced their potential need to address this area, with the arrival of another option possibly giving them the option to play a back three.

The Black Cats’ boss played with a back three at Ewood Park last season, so a system change can’t be ruled out.

Lyle Taylor

This may seem like a poor signing, but Taylor is a proven scorer at this level and like Ayala, he could be a decent squad option.

Depth is just as important as quality in the forward area and someone like the current Nottingham Forest man could be happy enough to sit on the bench or in the stands some weeks.

Players like that could be crucial in helping to maintain squad harmony – and the Black Cats would probably only tie him down to a 12-month deal too.

That should mean that he doesn’t block the path of promising youngsters coming through.

Lucas Joao

It would be difficult to see the Angola international putting pen to paper on a new contract considering the Royals need to keep their costs low after breaching financial rules and their business plan, with Joao potentially one of their highest earners.

That’s a massive shame for Noel Hunt’s side – because he is a proven goalscorer in the second tier and could be a wonderful signing for the Black Cats.

He may not be the fastest – but he’s brilliant on the ball and could be a real game-changer in the final third.

It feels as though they need another goalscorer regardless of whether Ross Stewart remains at the Stadium of Light beyond the summer or not – and Joao could be the perfect free agent to bring in.

He isn’t likely to be short of interest though, so they would need to move quickly to bring him in if they wish to sign him.