Raggett received his fifth yellow card of the season during the victory against Chesterfield and he will serve a one-match ban on Saturday.
Club captain Luke Waterfall will replace Raggett, who is set to join Norwich in January, in central defence for what will be his first start in over a month.
The Imps have midfielder Billy Knott available again after he completed his three-match ban last weekend.
Cambridge captain Leon Legge will serve a one-match suspension following his sending off against Wycombe.
On-loan Mansfield defender George Taft is expected to deputise for Legge, alongside Greg Taylor in central defence.
Striker Ade Azeez continues his rehabilitation from a knee problem and is the only definite absentee.
United have lost their last three games – to Swindon and Wycombe in League Two and Southampton in the Checkatrade Trophy.