When Matt Leinart entered the NFL he was in a pretty good position. Though the scouting report had him as an average NFL QB he was still drafted in the 10th spot which was above Jay Cutler, Greg Jennings and Antonio Cromartie.
Leinart's rookie season wasn't exactly horrible. He appeared in 12 games missing 4 due to a sprained shoulder. Connecting on 56.8% of his passes and throwing 11tds and 12INTs. In his second season his collarbone was broken early on against the Rams and Kurt Warner replaced him for the rest of the season.
In 2008 and 2009 he played a total of 12 games. Many experts thought that Matt had a chance to succeed in the NFL but his development had sputtered out quickly. "When he came out of USC he was so well-protected and had so much talent around him that it seemed like he entered the NFL already at one level, "Rob Rang said, "and he didn't show enough athletic ability as well as work ethic, at times, to improve."
Leinart was cut in 2010 by the Cardinals and was quickly signed by the Houston Texans. Leinart appeared in a garbage time situation against the Buccaneers and started against the Jaguars going 10/13 for 57 yards and a TD against them but broke his collarbone for the second time and was waived.
Teams continued to give him a chance, in 2012 the Oakland Raiders signed Leinart to be Carson Palmer's backup. Having a chance to impress people Leinart was inserted into a game after Palmer was hurt. If he was able to step up and make plays it would show the NFL that he was developing again, sadly he wasn't able to do that.
Matt Leinart's downfall wasn't all his fault. I really feel like Dennis Green never gave him a fair chance. The coaches didn't really support him or make him any better in developing him. Coming into the NFL he had a weak arm and below average mobility. In the NFL if you do not have immediate success you become an afterthought. It's so easy in this day and age to go and get someone else.