Glenn Loovens has become Sunderland's seventh summer signing.
The 34-year-old has put pen to paper on a two-year deal after being released by Sheffield Wednesday earlier in the summer.
He will offer some much needed strength in depth for Jack Ross at the heart of the Black Cats defence, with Alim Ozturk and Tom Flanagan his only senior options in that position.
Lamine Kone has not been part of the pre-season programme since making clear he wished to leave, while Papy Djilobodji has not returned following the conclusion of his loan to Dijon.
Jack Ross is expected to pursue one more option at centre-back, with the focus also turning to strengthening his forward line.
Bids have been made for Bradford City's Charlie Wyke and Cheltenham Town's Mo Eisa, though Sunderland could yet make more than two additions in that department.
They will also look to add a winger to their squad following the departure of Callum McManaman, who has rejoined Wigan.
Sunderland face St Mirren in their penultimate pre-season friendly on Saturday afternoon, though it is not clear whether Loovens will be involved.
He returned from his holiday to complete the deal on Friday.