The Blues suffered another setback during their 2-0 victory over Everton last weekend when first-choice goalkeeper Emi Martinez sustained a broken jaw.
The Argentine was stretchered off after a heavy collision with Everton defender Jarrad Branthwaite, with Mike Penders taking his place between the posts. Martinez has since undergone surgery and is expected to spend several weeks on the sidelines.
"What we know is he left the stadium conscious and right now he is in the hospital doing precautionary tests," Alonso said of Martinez after the game.
"It was concussion but more than that I saw only one clip. Hopefully it won't be too bad but we need to wait."
Chelsea were also without Pep Chavarria for the trip to Merseyside after the wing-back picked up an injury during training the previous day.
Chavarria had been hoping to make his third successive Premier League start, but Jorell Hato was selected instead.
Meanwhile, Gusto missed the Everton encounter through illness. However, the French full-back, who has occasionally featured in midfield under Alonso, is expected to be fit for Sunday's London derby.
Captain Reece James faces a considerably longer spell out of action. After suffering a knee injury in training, the defender underwent surgery and is reportedly expected to miss around three months.
Jamie Gittens is another absentee, having sustained an ankle injury while representing England Under-21s against Kazakhstan last month.
The winger returned to Chelsea for assessment and treatment, with Alonso confirming before the Bournemouth match that he would be unavailable for several weeks.
Enzo Maresca has made it his mission to help Phil Foden rediscover his best form and re-establish himself as one of England's leading players after the Manchester City midfielder ended his goal drought in spectacular fashion.
Virgil van Dijk believes Rio Ngumoha has a bright future at Liverpool after the teenage winger played a key role in their thrilling 4-3 Champions League victory over Villarreal at Anfield.
Arsenal manager Mikel Arteta fears Bukayo Saka could face another spell on the sidelines after the winger suffered a quadriceps injury during Wednesday's 2-2 Champions League draw against Bayern Munich.
Michael Carrick has admitted Manchester United's 4-1 defeat to Como was "not acceptable" after a disastrous Champions League performance on Wednesday, but insisted he was not worried about losing his job.
