The U.S. ski star has won a record 14 World Cup ski races at the Alberta resort, but Vonn wasn't yet certain after Wednesday's training run she's ready to race at Lake Louise this year.
Downhill races are scheduled for Friday and Saturday followed by a super-G on Sunday.
The reigning Olympic women's downhill champion completed her first official training run for a World Cup race since crashing and tearing ligaments in her right knee at the world championships in February.
Vonn then partially tore one of those reconstructed ligaments while training in Copper Mountain, Colo., two weeks ago.
So the 29-year-old admitted feeling nervous in the start hut Wednesday in a place she's so dominant that it's nicknamed "Lake Lindsey."
"Of course a little bit nervous," Vonn said. "Really happy to be back. First training run, first kind of real race situation since February, so it's been a long time and I'm really happy."
"Knee feels good, feels stable and just kind of play it by ear tomorrow and make a decision on the race."
Carolina Ruiz Castillo of Spain was fastest in training in one minute 57.40 seconds, followed by Germany's Maria Hoefl-Riesch and Slovenia's Tina Maze in third. Vonn was 2.13 seconds back of Castillo in 22nd.
Larisa Yurkiw of Owen Sound, Ont., is the lone Canadian and was 25th.
Vonn appeared to wear a brace on her right knee Wednesday. She was pulled away from reporters by a U.S. Ski Federation official after less than a minute of questions, but did say before departing her decision to race will depend on how her knee reacts to training.
Another training run is scheduled for Thursday.
"The biggest thing is making sure there's no swelling so the quad can react appropriately and fire appropriately," Vonn said.
Because of the setback in her knee, Vonn was forced to sit out last weekend's World Cup races in Beaver Creek, Colo. She requires more surgery, but wants to postpone the procedure until after the Winter Olympics in February.
"I'm just trying to make sure things are good with my knee and build confidence every day," Vonn said. "Sochi is obviously quite a ways away, so I'm trying to stay focused and focus on my knee and get the confidence back."
Vonn and golf star Tiger Woods revealed earlier this year they were in a relationship. Vonn accompanied Woods to tournaments during the summer, but he is not in Lake Louise.
Woods is hosting the Northwestern Mutual World Challenge in Thousand Oaks, Calif., and participated in the pro am Wednesday.
Vonn has races through trials and tribulations to some of her victories at Lake Louise, which gives her an aura of invincibility at the resort.
She's achieved a "Lake Louise hat trick", which is winning both downhills and the super-G, each of the last two years. Including her super-G win in 2010, she's won a record seven straight World Cup races.
Vonn won the first of her two downhills last year by 1.73 seconds, which is a gaudy margin considering tenths of seconds separate racers.
She did this despite arriving in Alberta drained of energy from a stomach ailment that hospitalized her for two nights earlier that month.
She was also under considerable pressure to win after she'd asked the world governing body of the sport to let her compete in the men's World Cup on the same mountain. FIS denied her request.
Her sweep in 2011 came a few days after she announced she was divorcing Thomas Vonn, her husband of four years.
Vonn executed an incredible piece of skiing in 2010 in a race she didn't win. She went down on her left hip entering a section of the course named Fall Away, but made an impressive recovery on the slope's face. Vonn finished second in that downhill to Hoefl-Riesch.
In 2009, Vonn crossed the finish line with blood dribbling from her mouth. Her knee connected with her chin during the race, yet Vonn still won the first of her two downhills that year.
"I'm so confident on this hill and I felt like this was the perfect place for me to come back," Vonn said. "Of course, I would have liked to come back at Beaver Creek, but it didn't work out.
"Hopefully this weekend will be good, but I have to play by it by ear and make a decision Thursday on whether I start competing on Friday."