The details are unknown, but Posey and the Giants have been discussing a long deal, as reported here earlier this week. It is believed he had been seeking a deal to make him a Giant for life.
A 10-year deal would not be out of the question for a star of this caliber.
The sides have been treating opening day as a deadline to get a deal done. Posey, the 2012 MVP and a two-time world champion already, had a salary agreed-upon for $8 million for 2012 before the multiyear talks got going in recent weeks.
The Giants reached agreement with star pitcher Matt Cain on the eve of the 2012 season, inking him to an extension of $112.5 million over five years that gave him $127.5 million over six years in total.