The Mexican striker joined Bayer Leverkusen from United last summer and starred in his debut season in Germany, scoring 26 goals in 40 matches in all competitions.
Chicharito feels he was not given the opportunity to reach his absolute best at Old Trafford, or during his loan spell with Real Madrid in 2014/15, and believes things may have been completely different had he been installed as their number one striker.
"If I had more chances at United or Real, I'd probably have been 'the star' there as well - we'll never know," the 28-year-old told FourFourTwo.
"I didn't have the chance. I never had the chance to play 20 games in a row so people could say, 'He's a good player who should stay' or, 'He can't be the star - he's not a good player'.
"Ask the United fans. The numbers are there. The difference is that Leverkusen want me on the pitch. The others didn't."