Benzema, 34, enjoyed a fine season last campaign as Madrid lifted LaLiga, the Champions League and the Spanish Supercup, scoring 44 goals in 46 appearances in all competitions.
Carlo Ancelotti's side have signed midfielder Aurelien Tchouameni from Monaco and centre-back Antonio Rudiger from Chelsea this summer, but they have yet to strengthen in attack having missed out on the signing of Paris Saint-Germain's Kylian Mbappe.
"There are lots of players who can play as a No. 9 because [a] Madrid [striker] isn't a typical No. 9 who... waits for balls, you have to move everywhere," Benzema said before Madrid's UEFA Supercup clash against Eintracht Frankfurt.
"Like the manager also said, there are lots of players. Afterwards in terms of signing another one [No. 9], you have to ask him."
"When you're missing the best forward in the world [Benzema] of course that affects the team. But we have solutions. Replacing Karim is impossible."
"Thibaut Courtois, for me, is the best goalkeeper in the world," Benzema said. "Afterwards Ballon d'Or, no Ballon d'Or, that I can't tell you."