Duo missing for Robins Swindon boss Paolo Di Canio will be without Andy Williams and Alan McCormack when they entertain strugglers Coventry. Striker Williams suffered a calf injury in last weekend's win over Bury and is likely to be out for up to a month. Adam Rooney replaced him on the day and may deputise again while Paul Benson offers further options in attack. Skipper McCormack is still struggling with a hamstring problem and will sit out the Sky Blues clash. Di Canio is boosted by the return of midfielder Gary Roberts. The winger returned to training earlier this week but Saturday may come a little too soon for him to feature. "Gary will join the group again full-time and we will see gradually," the Italian told the Swindon Advertiser. "I don't want to say yes completely, but why not - we will see. He's forced a bit more, didn't feel any reaction and delivered the ball well in training." Richard Wood is expected to be cleared to play for Coventry. The centre-back, already nursing a broken nose, was forced off just 31 minutes into Tuesday's Johnstone's Paint Trophy tie at York with a suspected fractured cheekbone. But Wood has been given the all clear and is now set to be in contention to start at the County Ground. That will come as a welcome relief to manager Mark Robins who, having seen his charges clinch a resounding 4-0 win in midweek to extend City's unbeaten run to four matches, could be tempted to stick with an unchanged XI. Callum Ball started in place of Adam Barton - the only change from last Saturday's 1-0 win over Bournemouth - and can expect to keep his place in attack following another impressive performance. Winger Gary McSheffrey (foot), striker Cody McDonald (knee), centre-back William Edjenguele (hip) and midfielder Conor Henderson (knee) will each again be assessed. But David Bell (hip) and Conor Thomas (knee) remain a way off.