Lions hooker under the knife
The 26-year-old went under the knife to repair cartilage damage, after suffering a knock to the knee earlier in the season.
Coetzee will be out of action for approximately four months.
He started the Lions' tournament opener against the Sunwolves in Tokyo back in February and also featured in their loss to the Highlanders in Week Three, but has been sidelined since.
Jantjies, who will be wearing a brace to protect his injured wrist if he passes a late fitness test, has been bracketed with fellow Bok Marnitz Boshoff at No.10 in the for Friday's encounter with the Crusaders at Ellis Park.
Ackermann said he is confident Boshoff and young Jaco van der Walt will not let the team down if they are called upon.
"We have worked hard on our depth at the Lions and we have always said we wanted two or three players of quality in each position," the coach told a media briefing.
"Marnitz [Boshoff] has played at the highest level [Springboks]," Ackermann said, adding: "We have faith in Marnitz and Jaco [van der Walt], should Elton not be available.
"They have been with us for a while, they know how we play and they bring something else to the table."
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