Major league baseball teams are reportedly lining up substitute umpires should the regulars strike at the beginning of the season.
American League President Bobby Brown, quoted by the New York Times, said: "What I did is alert the clubs that negotiations are in progress, they haven't been resolved and, with the season coming up, they had to find out who is available and who isn't."
A National League spokesman said the league had "not sent a bulletin" to its clubs, but refused to comment when asked if the league's teams had been told to arrange for substitute umpires.
The major league umpires contract has expired and negotiations have made little progress. In 1979, the umpires struck the first seven weeks of the season, and they struck a total of seven league championship series games in 1984.
In past strikes, local amateur umpires or minor league umpires were used.