The 28-year-old spent time on loan at both Mainz and Alaves before the club were relegated.
Now Bojan has revealed the comparisons to Messi generated pressure on his shoulders.
"You need to control the things you can do," Bojan told BBC Sport.
"My first year I scored 10 goals in La Liga. Then people started saying 'yeah, the new Messi'.
Barcelona news: Bojan is currently playing for Stoke in the Championship (Image: GETTY)
Barcelona news: Bojan lines up against Messi for Ajax in 2013 (Image: GETTY)
"You can do nothing about this. In the end, I know my qualities and I know I'm not Messi. I'm Bojan. If people say 'this guy was not the new Messi', yeah I was not the new Messi."
But even after moving to Roma and AC Milan, the tag seemed to follow the attacker.
"It's not easy," he added. "Messi scores three goals every game. If you score one goal, you're not Messi.
“When I went to Rome and Milan, you go there not as Bojan, you go as a new star, a new Messi.
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