Krstic already left the NBA once to play for the Russian league and according to wikipedia he only played 13 games there....(...sorry couldn't find a better source. Apparently, people go to Russia and their stats don't exist.)
Since he came back to play for OKC quickly it wouldn't surprise me if he passes up this offer and resigns with the Cs. They freaking need him that's for sure. Also, the luster of playing in Europe and other international leagues has faded after many players ended up in sketchy situations w/ not totally guaranteed contracts.