The free-agent defensive back signed a one-year contract Thursday and was placed on the non-football injury/illness list while he handles a personal matter, the 49ers said. San Francisco released cornerback Lowell Rose to clear room on the roster.
Wright had been traded to the reigning NFC champions last month for a conditional draft pick in 2014, but he failed his physical, nullifying the deal. Tampa Bay then released Wright.
"We're looking forward to Eric getting back to being the player that he thinks he can be and we think he can be," Harbaugh said after a 10-6 exhibition loss to the Denver Broncos on Thursday night. "That would be a great story for him to be able to do that. It would be great for us if he can get there. We'll work with him."
San Francisco needed depth in the secondary after cornerback Chris Culliver was lost to a season-ending knee injury Aug. 1. Harbaugh isn't sure when Wright will join the team.
Shortly after the trade, reports surfaced that Wright had been arrested a week earlier in Los Angeles on an unspecified misdemeanor charge. General manager Trent Baalke said the team was aware of the situation.
"We are pleased to welcome Eric to the 49ers organization and look forward to his contributions," Baalke said. "Eric is currently tending to a personal matter and he will join the team as soon as possible."
Wright was arrested in 2012 on felony DUI charges and was suspended for four games last season by the NFL for violating the performance-enhancing drug policy in his first season with the Bucs. He finished with 37 tackles and one interception in 10 games, all starts.
The 28-year-old Wright, a San Francisco native in his seventh NFL season, signed a five-year, $35.3 million contract with Tampa Bay last year. The Niners' move to trade for Wright immediately raised eyebrows after Harbaugh's comments during the team's June minicamp -- he made it clear he wouldn't accept players breaking the NFL's policy on PEDs for a perceived edge.
While Wright wasn't previously on the roster after the trade was nullified, Harbaugh made it clear his stance was the same.
"That hasn't changed," he said at the time. "I think our guys do a good job of playing within the rules."