SANTA CLARA —-- The 49ers capped a busy first day of free agency Tuesday by acquiring offensive tackle Jonathan Martin in a trade with the Miami Dolphins.
Martin, who left the Dolphins suddenly last season amid harrassment by Richie Incognito and other teammates, was obtained for an undisclosed draft choice. Martin played for 49ers coach Jim Harbaugh at Stanford and is expected to compete for the backup spot at both tackles.
The deal was announced by the Dolphins after 7 p.m.
"Big news," Martin wrote on his Twitter account. "Beyond blessed."
In another Tweet, he wrote: "Opportunities are few in the NFL... Can't wait to get to work #9erEmpire."
The 49ers had opened free agency with a sudden swap of safeties, adding safety Antoine Bethea, a two-time Pro Bowler from the Indianapolis Colts, after Donte Whitner left to join his hometown Cleveland Browns.
In other moves, the 49ers re-signed kicker Phil Dawson (two years) and cornerback Eric Wright (one year) and made another surprising trade: getting quarterback Blaine Gabbert in a deal with Jacksonville. Gabbert, the 10th overall pick in the 2011 draft, has been such a disappointment that the Jaguars parted company with him for a sixth-round pick and the possibility of more compensation depending on Gabbert's role with the 49ers in 2014.
That is not expected to be much, at least in the view of Bill Polian, the former Indianapolis Colts executive who now serves as an analyst for ESPN.
"I would not count on him to contribute to the squad," Polian said of Gabbert.
The secondary's overhaul could have the biggest impact, however. Part of that transition was cornerback Carlos Rogers' release after three seasons to help ease salary-cap constraints.