49ers sign Jonathan Martin

SAN FRANCISCO — Jonathan Martin is returning to familiar territory, months after he accused a teammate of bullying and left the Miami Dolphins.

The offensive tackle is headed back to the Bay Area to play for Jim Harbaugh.

Martin was traded from Miami to the San Francisco 49ers on Tuesday night, reuniting the lineman with his college coach at Stanford and a support staff he knows so well. In fact, Harbaugh publicly expressed his support of Martin last year.

The Dolphins announced the move late on the first day of NFL free agency. San Francisco then confirmed the trade, saying only that it would send an undisclosed draft choice to Miami and that Martin still must pass a physical to complete the deal.

“Big news.... Beyond Blessed ... Opportunities are few in the NFL... Can’t wait to get to work (hashtag)9erEmpire,” Martin posted on Twitter.

The 24-year-old Martin’s move cross country brings him back to Northern California, but he is already in town — back on the Stanford campus taking classes.

“This is great for him to get back on the field and he’s in Palo Alto right now. It couldn’t be much better,” his agent, Ken Zuckerman, said in a phone interview. “I just think everyone wanted this to happen. Harbaugh knows Jonathan, I think the Dolphins were compensated and Jonathan wants to get back on the field. It’s a good day.”

An investigation for the NFL determined last month that Dolphins guard Richie Incognito and two other offensive linemen engaged in persistent harassment of Martin, another offensive lineman and an assistant trainer.

Martin was a classics major at Stanford, while Incognito, 30, was kicked off his team at Nebraska and went on to develop a reputation as one of the NFL’s dirtiest players.

Martin, who protected Andrew Luck’s blind side at Stanford, was a second-round draft pick by Miami in 2012. He became a starter as a rookie but struggled at times while being shuffled between right and left tackle.

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Safety Donte Whitner headed out of the Bay Area for his hometown of Cleveland, the team wasted little time finding someone to fill his position.

Safety Antoine Bethea agreed to a $23 million, four-year contract with the Niners. Bethea announced on Twitter he had joined the 49ers, saying: “Glad to be a Niner!! Going to the Bay!!!”

Also Tuesday, veteran place kicker Phil Dawson received a new two-year contract after a sensational first season in San Francisco. Dawson announced on his Twitter page that he had re-signed, then the team made it formal.

The 49ers’ secondary also lost cornerback Carlos Rogers after three seasons Tuesday, an expected cost-cutting move by the team. Cornerback Eric Wright posted a photo on his Instagram account via Twitter of a new 49ers contract, but the team didn’t confirm he had received a new deal.

San Francisco also agreed to acquire quarterback Blaine Gabbert from the Jacksonville Jaguars for a sixth-round draft pick this year and a conditional pick next season, apparently finding a capable backup for Colin Kaepernick. The deal was pending a physical.

Gabbert started the first three games for Jacksonville last season before being benched in favor of Chad Henne, re-signed to a two-year contract worth $8 million Friday.

The 24-year-old Gabbert was the 10th overall draft pick in 2011 out of Missouri. He has thrown for 22 touchdowns in three NFL seasons, completing 414 of 777 passes for 4,357 yards in 28 games and 27 starts.