This means another team could try to sign Wallace to an offer sheet that the Steelers would have the right to match -- or get a first-round pick in return.
The highest qualifying offer for Wallace is about $2.75 million, nearly matching the amount that Pittsburgh is now under the salary cap. To franchise Wallace would cost Pittsburgh $9.5 million, which it currently does not have the salary-cap space to absorb.
At the scouting combine last week, Steelers general manager Kevin Colbert sounded determined to keep Wallace.
"Having a great player like Mike Wallace is not a dilemma," Colbert said. "We're going to do everything we can to make sure that Mike Wallace remains a Pittsburgh Steeler and I think that's Mike's belief as well. Usually when you have two parties that share the same goal, it's easier to achieve that goal."
Wallace, however, acknowledged last week that he might not be playing for Pittsburgh this season.
"[Pittsburgh is] where I would like to be, but we all know that it is a business and you have certain things you have to handle," Wallace told SiriusXM NFL Radio. "So if I have to go elsewhere, you know Pittsburgh will always be in my heart, but I have to do what I have to do."
Wallace had 1,193 receiving yards and eight touchdowns in 2011 and was selected to his first Pro Bowl. The 25-year-old has led the Steelers in receiving touchdowns the past two seasons after tying for the team lead in his rookie season.
Since entering the league in 2009, Wallace has the most touchdown receptions (19) on throws of at least 15 air yards in the NFL despite having the 12th-most receptions, according to ESPN Stats & Information.
The Steelers drafted Wallace in the third round (84th overall) in 2009 out of Mississippi.
Adam Schefter is ESPN's NFL Insider. Information from The Associated Press was used in this report.