The Egyptian had another off night at Anfield on Wednesday, though was not alone on that front with all his teammates suffering the same fate.
"There's over-reliance on Salah. Firmino's got to step up," Crouch told BT Sport.
"It felt like he was coming back into it, but Salah's the one scoring the goals.
"It was a shame when [Diogo] Jota got injured as he was pushing them to start.
"When Salah's not on it or he misses chances I just don't think there's enough. When Mane's out and Jota's out, there's not enough in the team to score goals."