If there is one player that the Blackhawks could absolutely not afford to lose at this early stage of the season, it was Duncan Keith. The reigning Conn Smythe winner, however, will be on the shelf for the next four to six weeks after undergoing surgery to repair a torn right meniscus according to the team.Keith had appeared in all six of his team’s games this season. He notched two assists and has averaged over 24 minutes of ice time a night.The team’s workhorse defenseman is going to be relied on heavily this season due to the relative shallowness of the Hawks defense. The team is also without veteran Michal Rozsival who continues progressing in recovery from an injury sustained last postseason.Over his career, the Blackhawks’ alternate captain has logged an average of 25-plus minutes of ice time. Additionally, Keith has been an incredibly durable defenseman for the club. He has never missed more than eight games in a season until now.There have been rumors that the club was already looking for defensive help on the trade market. Putting Keith on long-term injured reserve would give them some cap relief to make such a move, but that clouds the salary cap picture once Keith is ready to return. Besides, this is a time of year where making trades is next to impossible. How many teams are going to be willing to help the Blackhawks anyway? Keith has averaged nearly four more minutes of ice time than his next closest teammate so far this year, which means Brent Seabrook and Niklas Hjalmarsson should see their workloads increase significantly. Trevor Daley, who has had some early struggles early on, will also probably see his ice time feature more high-leverage situations. Young defensemen Trevor van Riemsdyk, David Rundblad and Viktor Svedberg are all going to have to step up in some way as well if the Blackhawks have to weather this storm without Keith.They certainly have enough offensive firepower to soften the blow, but the time spent without Keith in the lineup very well could impact the way the team plays. Despite the Hawk’s overall talent, Keith’s impact on everything is difficult to overstate.The Hawks managed to get by with shallow defense throughout last postseason after Rozsival’s injury. That was pretty much because Keith could play a mountain of minutes without having his play drop off. Without him, this blue line looks fairly average and the Central Division race is going to be a dogfight all year long.It will be interesting to see how the Blackhawks handle themselves during this period without Keith, especially after starting 3-3-0 with him in the lineup.