Lonergan was released by Leeds earlier this summer, despite still having a year to run on his contract.
The 34-year-old has since been on the lookout for a new club and has found the perfect match, with Tony Pulis' side in need of goalkeeping cover.
With fan favourite Dimi Konstantopolous now 40 and academy graduate Connor Ripley struggling during a loan spell at Burton last season the decision was made to bring in an experienced head to complete with undisputed No. 1 Darren Randolph and they seldom come more experienced than Lonergan.
The former Preston star has almost 400 career appearances to his name and he will now get the chance to add to that tally at the Riverside after signing a one-year deal.
Lonergan's arrival is likely to mean that Ripley leaves the club this summer, though it remains to be seen if that is on a permanent or temporary basis.
August 2, 2018