The former Ghana U20 shot-stopper joined the Phobians in 2022 but has barely played after being blighted by niggling injuries.
Antwi signed a three-year deal at the club and will be entering the final year of his contract next season but currently remains sidelined.
The 29-year-old said doctors initially diagnosed his injury to be a meniscus tear in his right knee but he continues to feel pain, which makes him unable to play.
He was supposed to recover within weeks, but having been on the sidelines for close to a year, Antwi said he suspects that there’s black magic behind his injury woes at Hearts.
“With the way my injury has been, I think there’s something behind it,” the goalkeeper told Sompa FM, as quoted by 3Sports.
“But if you used black magic on me, none of us are playing now. If you used black magic, the goal is now empty. None of the three goalkeepers is in the goal,” he said.
“I’ve never used black magic before. You might use it on me, but you will also not have peace. The doctors said it was a meniscus tear in my right knee. I feel pain when I bend my knee.”
Antwi previously lined up for Ghana Premier League sides Asante Kotoko, Medeama and Legon Cities. He was also a member of the Black Satellites side that finished third at the 2013 U20 FIFA World Cup.