Former boss Brendan Rodgers was willing to let Henderson go but the move failed to materialise.
Speaking on the proposed exit, Henderson told talkSPORT: "That was a crucial period in my career, not only my Liverpool career.
“I thought that moment was big, and it was a tough moment, but one that I feel helped me, looking back now.
“I don't know what would have happened if I didn't have that moment. It was tough at the time but thankfully it worked out okay in the end.
“To be fair to Brendan, he was brilliant with me after that point; he helped me grow as a player and as a person, and I really matured under him.
“It was a blessing in disguise really."