Aaron Brooks will miss the next 2-4 weeks due to a strained pectoral muscle, but that's not bad news by any means. After two performances worse than any quarterback could imagine, Andrew Walter will work the Raiders' offense during his absence. Walter took over during the first quarter for Brooks during this past week against the Baltimore Ravens, but was not very effective either.
Walter will almost definitely start against the Cleveland Browns on October 1st, since the Raiders have a bye this week. Walter was the Raiders' third-round draft pick last season. Against the Ravens, Walter threw for 162 yards and three interceptions and was sacked six times. He also fumbled three times, losing one of them.
Fantasy Update: If you even think about have Brooks or Walter on your roster, you must be desperate. You'd be better off taking a backup that will never play; at least that way, you won't accumulate negative points.