From the moment the Giants signed Buster Posey to an eight-year, $167 million extension before the 2013 season, the club insisted that Posey’s premium and critical position behind the plate contributed to the deal’s hefty price tag.

Brandon Belt’s new five-year extension, which runs through 2021, confirms the lack of any secret understanding between Posey and the Giants that he ultimately will move to first base full time to preserve his bat and health as he ages.

First base is now filled, and Posey no longer has to answer questions about a position shift.

“I’m glad Brandon is going to be here and he’s locked up, but it didn’t bother me to have to answer it every couple of weeks,” Posey said, smiling. “I really do believe it’s been more speculation than anything.”

Posey said the front office never sought his opinion on a potential Belt extension or discuss what it might mean for the catcher’s future, confirming for Posey that team officials have been truthful when saying publicly they want Posey to keep catching because of the value he brings behind the plate.

Posey said yes when asked again Sunday whether he wants to catch for the rest of his career. But he paused and added a vague qualifier, saying, “I want to be as productive as possible, however that is, as productive as I can be for the team the rest of my career.”

Henry Schulman is a San Francisco Chronicle staff writer.

Leading off

Affeldt hasn’t changed: Retired pitcher Jeremy Affeldt said he tumbled off the lift on a bunny slope at Mount Spokane on his first ski trip in 24 years.

— Henry Schulman

On deck

Monday

Off

Tuesday

at Rockies

5:40 p.m. CSNBA

Samardzija (0-0) vs. Chatwood (1-0)

Wednesday

at Rockies

5:40 p.m. CSN+

Peavy (0-0) vs.

Lyles (0-1)