Sosa, who earlier this year told the Cubs to trade him unless they would extend his contract, now says he would use his rights to block any deal.
Sosa's agents, Tom Reich and Adam Katz, met Sunday morning in Chicago with Cubs president Andy MacPhail.
"We told him don't even explore a trade. If you do try to trade him, he will not approve it," Katz said.
Sosa is signed through next season as part of a $42.5 million four-year contract. He then is eligible to become a free agent.
The Cubs and New York Yankees spent much of last month discussing a possible deal, but Chicago demanded more prospects than New York was willing to give up. Talks ended June 29 when the Yankees acquired outfielder David Justice from Cleveland.
MacPhail said the Cubs would cease all trade talk involving their top star.
"We were happy to hear that," MacPhail said. "We're happy that Sammy wants to stay in Chicago through 2001. I didn't really have any interest in trading the guy who drove in 300 runs the last two years for prospects."
By saying he would veto any deals, Sosa puts the Cubs in position of potentially losing him while getting nothing in return if he decides to leave Chicago as a free agent.
Many teams who fall out of contention trade their top players who are eligible for free agency in the months before their contracts expire.
Sosa, who followed up his 66-homer effort in 1998 with 63 more last year, is batting .305 with 23 homers and 74 RBIs.
The Cubs, who took two of three games from the crosstown-rival White Sox this weekend, trail NL Central-leading St. Louis by 15 1/2 games at the All-Star break.
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