Noun
(slang, boxing, derogatory) An inferior fighter in the sport of boxing. The insinuation is that an up-and-coming fighter takes on a "tomato can" to burnish his reputation and record.
(slang, sports) By extension, an opponent who presents little challenge.
(slang, boxing) A boxer who takes a dive, or loses a fight on purpose.
Source: en.wiktionary.orgA tween boy finds wrestling stardom through a magical mask in this family-friendly flick that’s more of a tomato can than a champion. Source: Internet
"If Joe Biden drops out and the DNC runs a tomato can, I will vote for the tomato can, because I believe the tomato can will do less harm than our current President." Source: Internet