Matt Chapman, perhaps the top position player left on the free-agent market, signed a one-year, $18 million deal with a $2 million signing bonus with the Giants on Sunday.

The deal includes a $17 million player option or a $2 million buyout for 2025, an $18 million player option or a $3 million buyout for '26 and a $20 million mutual option or a $1 million buyout for '27.

The move reunites Chapman with manager Bob Melvin. The pair spent five seasons together in Oakland from 2017-21.

Since Chapman turned down a qualifying offer from the Blue Jays in November, the Giants will have to forfeit their second-round pick in the 2024 MLB Draft as well as $500,000 from their international bonus pool.

• What's next after signing Chapman?

The deal figures to have ramifications for incumbent third baseman J.D. Davis, who played with Chapman at Cal State Fullerton from 2012-14. Davis, 30, is entering his final season before free agency and shares a similar skill set to Wilmer Flores, so he could become a trade candidate now that Chapman has been brought into the fold.

Chapman, who will turn 31 next month, should help stabilize the Giants’ infield defense and bring more continuity to a lineup that recently added two other everyday players in center fielder Jung Hoo Lee and designated hitter Jorge Soler.

Even with Chapman, the Giants still haven’t filled their more glaring needs in the starting rotation, which will be without Alex Cobb (left hip surgery), Robbie Ray (Tommy John surgery) and Tristan Beck (upper arm aneurysm) to start the year. Blake Snell and Jordan Montgomery are among the starters who remain available in free agency, so it wouldn’t be a surprise to see San Francisco continue to add before Opening Day on March 28.

It initially looked like 2023 would be a year to remember for Chapman. He was named the AL Player of the Month for April after leading all hitters with a 1.152 OPS and a 219 wRC+ during the season’s first full month. But that would turn out to be the zenith of his season.

After April 30, Chapman posted a .205/.298/.361 slash line with an 84 wRC+ and a 29.8% strikeout rate. His scuffles led to him being dropped into the lower third of the Blue Jays’ batting order, and he batted eighth during the team’s two postseason games. His 17 homers were his fewest in a full season since his 2017 rookie year.

Chapman’s bat has always created a lot of strong contact, and that didn’t change despite his struggles last season. His 56.2% hard-hit rate trailed only Aaron Judge among qualified hitters, and his 17.1% barrel rate tied for fourth-best in MLB, behind Judge, Shohei Ohtani and Yordan Alvarez.

Although Chapman’s defensive metrics have fallen in his two years with Toronto, he remains a very dependable presence at third base. The four-time Gold Glove winner and two-time Platinum Glove winner recorded five Outs Above Average at the hot corner last season, tied for ninth-most at the position.

Chapman, a first-round Draft pick of the A’s in 2014, spent his first five big league seasons with Oakland. He averaged a 120 wRC+ during that span, 10th highest among qualified third basemen. He recorded 24 homers and an .864 OPS in 2018, which he followed up with a career-high 36 dingers and an .848 OPS in 2019 -- the year Chapman made his lone All-Star team to date.