The Black Cats were immediately looking to strengthen following their promotion from League One, as several players weren’t offered new deals following the end of their contracts.
Sunderland also had a handful of loan players during the 2021/22 season who then returned to their parent clubs.
We’ve taken a closer look at what happened to the players who left Wearside at the end of the last campaign.
1. Thorben Hoffmann - Eintracht Braunschweig
If Hoffmann had played two more games for Sunderland last season he would have triggered a clause in his contract for the club to sign him permanently, following promotion from League One. Instead the 23-year-old goalkeeper returned to parent club Bayern Munich before signing for Bundesliga 2 side Eintracht Braunschweig, where he has started just two of nine league games this campaign. Photo: Martin Rose
2. Callum Doyle - Coventry
Sunderland elected to pursue other defensive targets after Doyle saw his game time reduced in the second half of last season. Still, his loan spell on Wearside from Manchester City was still encouraging, and led to a loan move to Championship side Coventry. After being named on the bench for the Sky Blues' first two league fixtures this season, Doyle, 18, has started the side's last four league games. Photo: Clive Mason
3. Nathan Broadhead - Wigan
Following the striker’s impressive loan spell on Wearside, Sunderland were keen to re-sign Broadhead and thought a deal was close. Instead, the 24-year-old joined Championship rivals Wigan on loan, after signing a new contract at Everton. Broadhead scored during his second match for The Latics after coming off the bench in a 1-0 win at Birmingham. Still, his seven appearances this season have all been as a substitute. Photo: National World
4. Lee Burge - Northampton
Burge returned to action at the end of last season following a period of absence due to heart issues. He was included in Sunderland's matchday squad and featured for the under-23 side but wasn't offered a new deal on Wearside. The 29-year-old then joined League Two side Northampton, where he has started every league game this season, with The Cobblers sitting second in the table. Photo: Pete Norton