The Los Angeles Dodgers offered left-hander Clayton Kershaw essentially a lifetime contract in the range of $300 million -- "an A-Rod deal" -- earlier this season, according to a source with knowledge of its scope and structure.

The two sides were unable to finish negotiations, sources say, because Kershaw was initially uncertain about committing to a deal so encompassing, and about having contract talks during the season.

But the negotiations progressed enough that there is confidence among some with knowledge of the talks that a long-term deal -- perhaps more conservative in length than the massive contract initially proposed by the Dodgers -- will be concluded this winter, with a significant portion of money being devoted to a charity of Kershaw's choosing.

Alex Rodriguez's current contract with the New York Yankees is the largest in baseball, a 10-year, $275 million deal that could reach $305 million if he achieves all of its incentives.

Kershaw's potential contract is expected to be the largest ever for a pitcher.

Earlier this year, Felix Hernandez agreed to a seven-year, $175 million contract with the Mariners, and Justin Verlander agreed to an extension that results in the Detroit Tigers paying him $180 million for the 2013-19 seasons. CC Sabathia signed a seven-year, $161 million deal with the Yankees after the 2008 season.