Most teams come into the preseason with a pretty good idea of who their quarterback is going to be to start the season. There are exceptions, of course, like Arizona, Tampa Bay, Cleveland, Minnesota and others this year, but for the most part the plan is set well before August. Where it can get really scary for teams and their fans, though, is when a designated starter doesn't play anything like a starter in preseason action. There are several teams this year that are facing this problem. This can make it hard to know who should and will start, and what we can expect from them when we do. It can challenge the confidence of the teams as well. Here's a look at five quarterbacks who have failed to step up to the challenge presented to them so far this preseason.

Matt Cassel, Kansas City Chiefs - Cassel was lousy in the first preseason game, and only okay in the second game. The problem isn't necessarily that he hasn't been as good as he was last year - no one could realistically expect him to be given the difference in talent between his new team and his old one. The problem is that Cassel has failed to differentiate himself from those that he is supposed to be a significant upgrade from. He was badly outplayed by Brodie Croyle in the first game, and Matt Gutierrez was almost as good as him in the second game. Luckily for Cassel, Tyler Thigpen has been dealing with injuries so he hasn't been at his best. The Chiefs made a significant investment in Cassel, and for the sake of their aggressive rebuilding plan they need him to look like he is worth it. So far, that hasn't really been the case.

Jason Campbell, Washington Redskins- The Redskins flirted with a lot of quarterbacks in the offseason before settling on Campbell again. Some players might use that perceived slight as a motivation to raise their game to another level. It doesn't appear that that's the case for Campbell. In two games, Campbell is a pathetic 4-for-13. He's getting worse, too - he was 1-of-7 in his last game. The only saving grace for Campbell is that no one else is stepping up to really pressure him. The only player putting together good stats is undrafted rookie Chase Daniel, and his two touchdown places came late in the game against Pittsburgh after the starters were long gone.

Kyle Orton, Denver Broncos - Watching Orton this preseason you almost get the sense that he is feeling the pressure that he is under replacing a Pro Bowler, and he hasn't yet come to terms with it. Most of the time he has looked pretty good. The problem is that when he has looked bad he has been awful. He threw interceptions in each of his first three drives in his first game, and he had a bizarre interception thrown with his non-throwing hand in the second game. If Orton relaxes and plays his game he is more than competent enough for the Broncos. If he keeps panicking, though, then things will get ugly. If he is feeling the pressure then it won't help that the national eye is focused on the team and it's psycho young coach.
 
Kellen Clemens, New York Jets - Everybody knows that Mark Sanchez is going to be the starter soon and hopefully for a long time to come. You have to believe, though, that the team would be happier if they could ease Sanchez into the starting role - especially because this could be a competitive team this year. Unfortunately, Clemens hasn't stepped up to the challenge. It's probably not that surprising that Clemens doesn't appear to be up to the task of buying the rookie some time - he hardly played at all last year, and it's not like he was tearing the league up when he was playing.

Kerry Collins, Tennessee Titans - Last year I expected Collins to play like the old guy that he is. I was wrong. This year I still expect him to play like an old guy, and so far I'm feeling okay about that prediction. Collins is putting the Titans in a rough position. They either need him to be really good or really bad. If he's really good then there is no question about what the quarterbacking situation should be in Tennessee. If he's bad then the team can easily hand the reins to Vince Young without any questions or concerns. The way Collins is playing now, though, there will always be a problem. They can't start Young in his place without raising questions, but he's not good enough right now to really ensure that this team succeeds. In other words, if Collins is playing just slightly less than average football then the team is likely headed towards a quarterback controversy.