Pittsburgh cut Lockhart on Friday.
Lockhart, 23, went undrafted out of Baylor in April. He signed with the Steelers as a college free agent.
He spent two years at Texas A&M and two at Baylor, playing 28 games over four seasons. Lockhart made 54 tackles, seven sacks, a forced fumble and two pass breakups.
Last season at Baylor, Lockhart made 8.5 tackles for loss and six sacks.
James Lockhart retires after 49ers claim him off waivers originally appeared on Pro Football Talk