Yeah. Look at 2002.
New Head Coach, RB coming off a major knee injury, and a lack of viable receiving threats. We had lost Jerome Pathon and Ken Dilger in the offseason, and Wayne was in his second season and hadn't really blossomed yet. Harrison had a season which is on the short list of canidates for the best year ever for a WR, with 143 catches (the next best EVER is 123), and the fourth most yards ever in a season at 1722.
But the point is, that team got by solely on Manning to Harrison. Obviously, that one-faceted a team isn't going to get very far in the playoffs. Harrison had more catches than the #2 and #3 receivers and the #1 TE combined, 143-136. James, while he caught 61 balls that year, only managed a 3.6 YPC, and didn't break 1000 yards for the only year of his career in which he was healthy. And he only scored 2 rushing TDs.
On top of all that, Mike Vanderjagt had his worst statistical year ever, and while their points allowed was pretty decent, their run defense was mediocre at best and they had a -5 turnover ratio.