Following back-to-back drops from the Premier League to League One, many Sunderland fans could not see the light at the end of the tunnel.

But following Ellis Short's sale of the club to Stewart Donald, the debts being written off and promising young manager Jack Ross coming in, there is a renewed sense of optimism at the Stadium of Light.

Sunderland are the big fish in League One - they will be the team to be feared.

But they will need a busy summer of transfer activity to ensure they are in the best position possible to make an instant return to the Championship.

Their high-earning players from the Premier League era need to be axed and more suitable League One signings need to be made.

Ross will be armed with a decent war-chest given that the Black Cats still have parachute payments and are likely to generate funds from sales.

Here are three players who would make Sunderland a serious force next term.

John O'Shea has gone to Reading, Marc Wilson has been released, Jake Clarke-Salter has returned to parent club Chelsea and Lamine Kone will be made available for transfer because of his large wages.

This means centre-back is a priority and former loan star Nedum Onuoha would be an ideal capture on a free transfer.

The 31-year-old is experienced, with over 370 appearances in the top two divisions, and reliable at the back, making him the perfect man for the job at Sunderland.

Exciting winger Morgan won the Scottish Championship Player of the Year under Ross at St Mirren last year, guiding his team to the title in the second tier.

The 21-year-old might not be deemed ready for Celtic yet and a loan move to England would aid his development.

The Scotland international is too good for League One level but his links with Ross make this a realistic transfer deal that could improve Sunderland so much.

If Sunderland could pull off the signing of £675k-rated Maddison this summer, they would arguably have the most dangerous attacking midfielder in the division.

With 10 goals and 21 assists last season, the 24-year-old showed yet again that he is a top performer at League One level.

Peterborough United have transfer listed their star man for the sake of his own career and he will probably fancy a Championship move, but Sunderland should still approach the former Newcastle United youngster with a tempting offer and a long-term project in mind.