Vonn was sixth after the morning downhill and clawed back one place in the slalom run to finish 0.85 seconds behind winner Wendy Holdener of Switzerland in St. Moritz.
Holdener's compatriot Michelle Gisin was second, 0.05 secs back, ahead of Austria's Michaela Kirchgasser, who also took third in 2015.
Home favorite Gut, Vonn's biggest rival for Sunday's downhill, crashed in training for the slalom and was airlifted to hospital.
She tore her left anterior cruciate ligament and sustained other knee damage, according to the Swiss Ski Federation.
Gut, who won bronze in Tuesday's super-G, is the reigning World Cup overall champion but her duel with Mikaela Shiffrin for the overall Crystal Globe is over.
Vonn, who won her only two world titles in 2009, taped her ski pole to her hand Friday after a loss of grip caused her to get distracted and ski out of Tuesday's super-G.
Her right hand is still recovering from nerve damage after she broke her arm in training in November.
The 32-year-old's best chance of gold is in Sunday's downhill.
"It was good to charge in the [combined] downhill," the 2010 Olympic downhill champion told reporters.
"It still wasn't my best skiing but I think it was a really positive step forward. It's nice to get race-simulated downhill under my belt."
Vonn is the second most successful ski racer of all time with 77 World Cup wins.
Sweden's Ingemar Stenmark holds the record with 86.