The safety, who many didn't expect to return to the 49ers, will re-sign with the team on a one-year deal, NFL Network insider Michael Lombardi reported Monday, citing a league source.
"We'll see," Harbaugh said.
The fifth-year veteran was brought back to bolster a banged-up secondary.
Smith, who started seven games for the 49ers in 2010, produced a vague tweet Monday after word of his injury leaked.
"Everything happens 4 a reason & I believe it," Smith wrote. "Just wished it wouldn't have happened right now. But with God on my side I know it will be OK."
Goldson played his first four NFL seasons with the 49ers, finishing with 80 tackles, one sack and an interception in 2010 -- but he said last week via his Twitter account that he didn't expect to be back after watching his team sign others who play his same position.
Goldson has started all 32 games at free safety over the past two seasons.
"To answer sum of the ?'S I'm not sure wht tht move by the 9ers was for, I guess to scare me ... well it didn't work. Try again," Goldson tweeted. "I'm definitely keepin an open mind. Meanin I won't mind takin my talents else where to a place where I'm wanted"
"Sorry guys thanx for all ur support but not gonna be back. See ya," he tweeted last Thursday.
Earlier, he said, "I wanna be in San Fran and in camp jus as much as u fans want me to be but as we all experienced the last 4mnths, its a business side to it."
Also Monday, the team announced the signing of rookie tight end Chris Blohm to a three-year deal. A San Francisco native, Blohm had 27 catches for 270 yards and two touchdowns last year at Yale.
The Associated Press contributed to this report.