The Serbian had been out since September after suffering a recurrence of a knee injury but started United's 1-1 draw with Swansea last week before making the bench for their 4-3 Boxing Day win over Newcastle.
And Giggs believes the center back has been a big miss, telling Absolute Radio: "He’s a great defender, a world class defender, so we’ve no doubt missed him over the last year or so."
The Welshman went on to express concern over his side’s current defensive frailty, conceding the Red Devils would like to have kept more clean sheets.
“Yeah, I think at the moment it’s a case of the team scoring more goals than the opposition,” Giggs said. “We’ve not had too many clean sheets which everyone wants."
“We are top of the league, a bit of daylight in between us and City so we can’t complain but yeah, we’d probably like a lot more clean sheets.”
Giggs also praised West Brom manager Steve Clarke ahead of the Baggies' trip to Old Trafford on Saturday.
“Steve Clarke has done a great job after a few assistant managers’ jobs. He’s took control of the team and he has took it on to that next level," he continued. “Every season you have a team who surprises people and West Brom could be that this year.”