Matt Chapman spent the last week in the Bay Area working out with Marcus Semien and came to a conclusion: The A’s need to sign their MVP-candidate shortstop to a contract extension.

“The A’s should pay him while they have the chance,” Chapman said of Semien, who can be a free agent after the season.

Moreover, Chapman, Oakland’s two-time Platinum Glove third baseman, would very much like to ink a long-term deal himself.

“I’ve been telling them: I’m ready. If the offer’s right, I’m willing to sign with the A’s,” Chapman told The Chronicle. “I want to be here.”

Chapman, who is represented by super-agent Scott Boras, declined to specify the number of years or a dollar amount he’d be looking for but, he said, “They know. It would have to be a long-term deal, obviously. But I love it here. They’ve been great to me, (owner) John Fisher, (vice president of baseball operations) Billy Beane, (GM) David Forst. It’s a no-brainer for me if the offer is right and it’s there, I want to do it.”

There haven’t been talks recently, Chapman said, “but I’m sure that it will circle back soon. Usually those things pick up more in spring training.”

Also on Chapman’s wish list, a long-term deal for Gold Glove first baseman Matt Olson. “There’s no more sure bet than that kid right there,” Chapman said. “I hope so. I think they do, too. I think they’re just trying to figure out the stadium and once they do, everything will snowball.”

The A’s never have given a player a bigger deal than third baseman Eric Chavez’s six-year, $66 million extension in 2004 and long-term deals for Semien, Chapman and Olson could wind up totaling close to $300 million. Oakland’s projected Opening Day payroll is about $100 million, but the A’s repeatedly have said once they have a new stadium, they’ll be in a better position to be able to retain their top talent. Oakland is focused on a site at Howard Terminal and still hopes for a facility by 2023.

Susan Slusser is a San Francisco Chronicle staff writer. Email: sslusser@sfchronicle.com Twitter: @susanslusser