The 11-year veteran will announce his retirement at a Wednesday news conference, the team declared Tuesday.
"I knew that this was the time for me to step away: happy, healthy and thinking fondly about my experience," Gross said, per the Panthers' official website. "I didn't want to leave until I felt the team was back in a good position for sustained success. The team is there now."
General manager Dave Gettleman said last week at the NFL Scouting Combine that Gross was "mulling" a return, but that the left tackle "earned the right to make" the decision on whether or not to come back or walk away.
Carolina quarterback Cam Newton undoubtedly will miss the stout blocker protecting his blind side.
There was speculation the Panthers might use their No. 28 overall pick in the 2014 NFL Draft on an offensive lineman, and Gross's retirement makes that more likely. The cap-strapped Panthers aren't likely to be in the bidding for the top, high-priced offensive tackles on the free-agent market.