Zayd bin Suhan says regarding the story of the Islam of Sayyiduna Salman (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) asked: "Whose slave are you?" I said: "Of a woman of the Ansar, who has put me to work in her garden." He (peace and blessings be upon him) said: "O Abu Bakr (may Allah be pleased with him)!" He said: "O Messenger of Allah, at your service." He (peace and blessings be upon him) said: "Buy him." So Sayyiduna Abu Bakr (may Allah be pleased with him) bought me and set me free.
Note: This narration differs from the earlier narrations. It is possible that he did not obtain his freedom because one tree did not bear fruit, so the Prophet (peace and blessings be upon him) replanted it with his own hand, and that in the meantime Abu Bakr (may Allah be pleased with him) bought him.
The authenticity of some of these narrations is open to question.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب المكاتب / 21627