Cape Town - Liverpool's 1-0 victory over Stoke in the first-leg of the League Cup semi-final came at a price as Philippe Coutinho and Dejan Lovren suffered a hamstring injuries.
After Coutinho and Lovren walked off with hamstring injuries, Jordon Ibe converted from close range before half-time after Joe Allen diverted a cross from Adam Lallana into his path.
Fourth-choice defender Kolo Toure was also holding the back of his right leg in the final minutes.
For Klopp, who went into the match missing first-team players such as Martin Skrtel, Daniel Sturridge, and captain Jordan Henderson, two more injuries tarnished the victory.
"It's a big shadow over the game for us," Klopp said, acknowledging he may need new signings.
"I don't know how serious, and we have to wait for this. In this situation with no center-backs fit, I would say (transfers) it's something we could look at."
Klopp decided to replace his only fit striker, Christian Benteke, with attacking midfielder Adam Lallana, who comprised a three-man attack alongside Coutinho and Roberto Firmino.
The trio ensured Liverpool began the game at a relentless pace - harrying Stoke's defense when it had possession and once the ball was won back, they passed it swiftly and intricately, pulling opponents out of position with their movement.
Firmino and Lallana both had shots from range well saved by Stoke goalkeeper Jack Butland, before Liverpool's momentum was abruptly halted when Coutinho went down off the ball, clutching his left hamstring.
He was replaced by Ibe, and Liverpool was disjointed further when Lovren stayed down after stretching to make a block and hurting his right leg.
With no central defenders on the substitute's bench, Klopp brought on midfielder James Milner, and Lucas Leiva partnered Toure in a makeshift central defense.
But Ibe delivered Liverpool's breakthrough. Lallana latched on to a neat forward pass down the right by Milner and played the ball into the penalty area. Allen helped the ball on to Ibe, who controlled and poked the ball past Butland.
Stoke replaced defender Geoff Cameron with striker Jonathan Walters at halftime, looking to exploit Liverpool's backline.
The host was galvanized by Walters' presence, and some last ditch blocking from Toure and Lucas denied Stoke in the first 10 minutes of the second half.
The pressure on Liverpool briefly relented as Ibe and Firmino were denied by Butland, but Stoke came back again with the introduction of substitute strikers Joselu and Peter Crouch.
Joselu brought a neat save out of Simon Mignolet when his shot from range was deflected, and Walters dragged a shot wide after forcing an opening in the last minute.
The second-leg is at Anfield is on January 26.
Everton hosts Manchester City in the other semi-final on Wednesday, January 6.