Long will miss Southampton’s match against Sunderland today with the knee injury suffered in Tuesday’s 2-0 defeat at Bournemouth.
But Southampton manager Ronald Koeman expects Long, who picked up a hamstring problem against Chelsea last Saturday, to be fit to face Stoke City on March 12.
He said: “Shane will not be available for this weekend.
“It is a different type of injury and we have good hope that he will be fit for next weekend but unfortunately he will not be available for this weekend.
“Shane took a knock up his knee against Bournemouth.
“It is painful for him but I am sure it will not be a problem for next weekend.”
Meanwhile Ireland keeper Shay Given is racing against time to be fit for the European Championships.
Stoke City boss Mark Hughes is “hoping” that Given will recover from a knee injury before the end of the season.
Given, who has won 133 caps for Ireland, has not played since twisting his knee against Germany last October.
He has undergone surgery at the Aspetar facility in Qatar after suffering a setback in recovery but is now in light training as he battles to prove his fitness to win a place in Martin O’Neill’s squad for France.
Hughes said: “It’s been a long time and we’re hoping he’ll be fit before the end of the season.
“Shay is now back out on the grass, which is encouraging.
“He’s working with our goalkeeping coach Andy Quy but it’s early days.
“He’s not doing all the elements of the sessions — but he is back on the grass.”