#2 Jeff Hardy

Another Superstar that required knee surgery was Jeff Hardy, who had to relinquish the SmackDown tag team titles earlier this year to have the procedure.
Reports had earlier suggested that he would be cleared to wrestle by the end of November, and it is likely that he is back in the pink of health, but issues away from the ring could cause him to not return this year.
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According to Fightful, Hardy is not expected to return soon as he's "taking care of his personal issues". These personal issues could be him being arrested for driving under the influence. We could possibly see him return next year, though, as he still has some months remaining on his WWE contract.
#1 Lars Sullivan
Lars Sullivan, incidentally, was one of the last Superstars to be involved in a feud with Jeff and Matt Hardy on WWE television. The former NXT Superstar is also out with an injury, and needed knee surgery.
Sullivan was reported to be out for anywhere between 6 and 9 months, and Fightful recently revealed that he could return in the summer of 2020.
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