Thiem reached the semifinals via walkover after Gael Monfils withdrew from their quarterfinal with a strained left Achilles.
Oft-injured Monfils said he'd felt discomfort in his ankle for a couple of days and had been receiving treatment, but the pain was worse after his fourth-round win over Philipp Kohlschreiber on Wednesday night.
"I knew he had nothing to lose, and I had to be really disciplined with myself", Raonic said. "Then we taped it".
"Tonight I tried to hit a little bit and I can't compete 100 percent". I'm just trying to play. "Because I was playing great tennis, feeling strong".
"I was really surprised", Thiem said, who was waiting to be taken to the court when he realized there was a problem". "I think we'll see interesting points tomorrow".
Serbian teenager Kecmanovic failed to convert any of his three break-point opportunities against a ruthless Raonic, who unleashed a torrent of punishing groundstrokes on a sunny and breezy day.
Thiem, ranked eighth in the world, withstood 17 aces from the rangy Canadian, gaining the only break of the contest in the third set.
Raonic's serve wasn't at it's booming best.
Federer was looking forward to the match and the chance to break out of a tie with Novak Djokovic for most Indian Wells titles, but was sorry to miss a meeting with Nadal. "He was pushing me back, and then he was aggressive from the very first ball", Raonic said. "But there's other things I'm doing well, for sure".
Williams' right knee was taped and she did not appear to be moving easily or serving with much pace.
While the 130th-ranked Kecmanovic fell short in his bid to become just the third lucky loser to reach the semifinals of a Masters 1000 event, he can regroup for the upcoming Miami Masters - where he has been given a wild card into the main draw. Kerber will play Belinda Bencic in the semifinal.
The Austrian said it would "mean the world" to break through for a Masters crown, but noted it would be a tall order against 20-time Grand Slam victor Federer - who is coming off a remarkable 100th career title in Dubai last month. That is the 32-year-old's best start to a season in 15 years on the ATP Tour.
"It's always something special to play [Federer] and also something special to compete in a Masters 1000 final", Thiem said after his semifinal match. She broke Williams in the match's longest game that went to deuce five times when Williams' forehand went wide. "When you get an afternoon off, you take it", said the 37-year-old Federer, the oldest finalist in tournament history.
Williams has not made it farther than the quarter-finals at any Premier Mandatory or Grand Slam tournament since last year's BNP Paribas Open.
"Paul was an extraordinary man, colleague and friend", Richard Lewis, chief executive of the AELTC, said in a statement. Hutchins, who had suffered from motor neurone disease, played professionally and spent 13 years as Davis Cup captain, taking Britain to the 1978 final against the United States.