Sunderland boss Keane: Etuhu's Nigeria call bad news
Keane has had some time to get used to the idea following the 25-year-old midfielder's elevation to the senior international ranks earlier this season.
He said: "Of course it is bad news, but it's out of our hands.
"There are a lot of clubs worse off than us - some have four or five players away.
"We are disappointed because the size of the squad here is not the biggest and injuries or people away are the last thing we need.
"But Dickson has been doing well and you cannot stop a player going away and representing his country. We wish him well.
"Hopefully, they will get knocked out quickly and he will be back with us!"
However, Keane admits he knew the situation when he signed Etuhu.
He told the club's official website: "When we signed Dickson, we knew what we were getting ourselves into, we knew he could be called up for this tournament.
"It could be at a better time of year but as I say, we are not the worst hit."