Ackermann senior will today name his match 23 to face the Cheetahs at Ellis Park on Saturday and there's a good chance Ruan could be pencilled in at No7.
The baby-faced Ackermann was on the bench in overseas tour matches against the Sunwolves and Highlanders.
Last weekend, in a losing cause, he came on and scored the try that denied the defending champions a bonus point.
Shimlas and Leopards coach Jonathan Mokuena said the 20-year-old had all the tools to slot in for the hard-grafting Tecklenburg.
Said Mokuena: "What I know about Ruan is that he's a physical player. He doesn't shy away from contact.
"His style of play will fit in nicely with the Lions game plan and he will bring the physicality that they need from their loose forwards.
"He will definitely do well and stick up his hand for future starts if he gets the nod from the coach."
With Fabian Booysen also out with an eye injury, Tecklenburg's starting spot will be contested by Ackermann and Robert Kruger.
In Kruger's favour is that he is a genuine line-out option, having spent considerable time as a No 4 lock.
Mokuena said the loss of Tecklenburg would be felt.
Tecklenburg was the second leading tackler in Super rugby last year.
But said Mokuena: "The Lions drill their players in such a way that whoever comes in will be able to do the job."
