Zamora was sent off for a high boot on Wigan's Jordi Gomez, and Redknapp has admitted that his side will miss the presence of the 32-year-old.
The former Spurs boss told reporters: "Bobby's sending-off was a rash decision and missing him for three games is a big loss.
"It was a crazy challenge and it's cost us dearly because we lost him for most of that game and for the next three matches. He should be disappointed.
"He's not 100% fit, you can see that, but he's still a good player."
The former Fulham forward will miss the first of three Premier League fixtures this weekend, when Queens Park Rangers play Everton.