Bournemouth boss Eddie Howe hopes to have Dan Gosling available before the end of the season.
Howe admitted his staff had been "slightly baffled" by Gosling's recurring calf injury after a number of scans showed what appeared to be "no major problem".
However, Gosling travelled to London to undergo an additional scan which revealed further information ahead of the trip to Sunderland.
Howe told the Daily Echo: "Dan had a more detailed scan than was possible here and that found a slight problem with one of the muscles in his calf.
"He will be out this weekend. How long he will be out, we're not sure but we hope to get him back before the end of the season."