We interrupt this report on rookie wide receivers to bring you...a rookie tight end. There aren't that many tight ends to discuss for fantasy purposes, but Greg Olsen (31st overall) is good enough to be on your list.
Olsen comes out of the same Miami program that produced Kellen Winslow Jr and Jeremy Shockey. So the first thing to know about Olsen is that he'll probably do something stupid that will cause a serious injury. That seems to be part of the training for tight ends at Miami.
If he can stay healthy, then he needs to get by Desmond Clark. Clark finished 2007 in tenth place among TEs in the league in receiving yards (626) and tied for fourth in touchdowns with six. However, Clark's totals were skewed by two games where he rang up 211 of those yards and 4 of those touchdowns. Other than those two huge games, he was fairly unimpressive. The Bears clearly felt they needed a tight end that can both block and provide an outlet for Rex Grossman so I expect to see Olsen as the starter for the Bears right away.
Considering Olsen's talent and the underwhelming group of wide receivers in Chicago, I think Olsen will be a usable fantasy tight end right away. I wouldn't be surprised if Olsen ended up with 700 receiving yards and six or seven touchdowns. Considering how few quality tight ends there are in fantasy football, Olsen should be a solid contributor to your fantasy squad.