BMW factory driver Alexander Sims will be on standby to make his Formula E debut for the Andretti team in place of Robin Frijns at Monaco this weekend.
Frijns, who also races for the WRT Audi GT squad, missed the opening round of the Blancpain Endurance Series at Monza after injuring the ligaments in his right knee while on a training run.
Although he returned to racing action in the Blancpain Sprint Series round at Brands Hatch last weekend and is set to drive at Monaco, Andretti reserve driver Sims is on call in case Frijns has difficulty with the injury.
"We will have Alexander at Monaco just in case there are any issues, but it is our plan to run Robin," Andretti team principal Roger Griffiths told Autosport.
"I've spoken to him today [Monday] and he's fit and ready to go."
Sims, who is racing in the IMSA Sportscar Championship for the Rahal Letterman Lanigan BMW team this season, has tested several times for Andretti developing its car for the 2016/17 season.
He is also likely to get a run in the 2017/18 Andretti development car in the coming months.
Frijns is confident of being able to race after being comfortable behind the wheel at Brands Hatch, although will check he is able to complete the in-race car swap when he arrives at Monaco.
"I have a brace on," said Frijns. "It's alright, driving I don't have any issues, no pain or whatever, just the driver swap."
"It's quite stiff still so it's not the easiest, especially in a small GT car like an Audi."
"It's just the few seconds I need for the pitstop, which could be painful.
"It's just the brace that keeps everything tight; no worries, no big problems."
Frijns has so far scored eight points for his sixth-place finish in the season-opening Hong Kong ePrix in the current Formula E season.
The Dutchman plans to undergo surgery to resolve the injury for the long-term at the end of the season.
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