Major league umpires went on strike Saturday after contract talks broke down, and baseball prepared to open the season Monday with amateur replacements.

One year after teams locked out players for 32 days and delayed the season's start by a week, major league umpires walked out for the sixth time in 21 years.Amateur umpires scrambled to ballparks on short notice Saturday for 12 exhibition games and were set for eight more on Sunday. The American and National leagues had prepared for a work stoppage by assigning amateurs for the season-opening games.

Richie Phillips, head of the Major League Umpires Association, said the 60 umpires struck because they were faced with a management lockout starting Monday, when eight openers are scheduled. Robert Kheel, management's negotiator, denied owners had decided on a lockout, but did not rule out the possibility that they would.

"All indications were that a deal would be done," Phillips said before returning home to Philadelphia.

Under the expired four-year contract, umpires were paid from $41,000 to $105,000 per season, depending on seniority. The leagues said they had offered to increase the minimum to $57,500 and the maximum to $155,000.