According to the USDA, meat that's been thawed in the fridge can be safely refrozen. Meat thawed on the counter is not considered safe to refreeze as-is.
The Rules for Safely Refreezing Thawed Meat

It happens to everyone: you pull a roast or a chicken out of the freezer meaning to cook it the next day, then life gets in the way. Despite what a lot of people think, you can actually refreeze thawed meat — if you follow a couple of rules.
Know the Fridge Rule
Understand the Quality Tradeoff
Refreezing causes moisture loss, which leads to drier, tougher meat, and each freeze-thaw cycle changes the structure of the proteins. A good rule of thumb: if the partially thawed item still has ice crystals throughout, it's safe to refreeze; if it's fully thawed with no ice crystals left, it should be cooked, not refrozen as-is.
Cook It First If It's Fully Thawed
Even if meat thawed on the counter is completely thawed with no ice crystals left, you can still freeze it — just cook it first. Once it's cooked, it's safe to freeze again for later.
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