The England centre-half will be missing for the next three games after the FA upheld the red card given to him by referee Stuart Atwell at Arsenal on Saturday.
It will deny him a chance of facing former club Aston Villa this weekend, but midfielder Holden believes there is enough experience in the squad to cope with his absence.
“Gaz has been a big player for us and is obviously an important part of the defence but whoever comes in has got a lot of experience and has played a lot of games in the top flight.
“That’s the way football goes because you have got to shrug off the setbacks. We have got to make sure we really dig deep and show how strong our squad is.”
Andy O’Brien looks likely to deputise at Villa Park, although Owen Coyle also has the option of playing the versatile Sam Ricketts at centre-half.