The Oakland Raiders are all-in on the Derek Carr bandwagon. The organization believes he has the ability to eventually develop into a franchise quarterback. But Carr and the Raiders disappointed in their 30-23 home loss to the Arizona Cardinals Sunday night (the third and most important preseason game).

In two-plus quarters, Carr looked uncomfortable in the pocket and failed to consistently connect with his receivers. Overall, he completed just 18-of-34 passes (53 percent) for 213 yards and one interception for a passer rating of 60.1. Yikes. Even with his impressive rapport with rookie Amari Cooper (four catches, 62 yards), that was a bad outing.

Fortunately for Raiders fans, it was just one incident in an otherwise promising offseason of development for Carr.

"However, Carr has been pretty darn good the rest of the summer," ESPN Raiders reporter Bill Williamson wrote. "He was solid in the first two preseason games. Carr, the only rookie quarterback to start all 16 games last season, is clearly improving this year.

"He is still a work in progress. He still needs to get better in the deep game and show more consistency. But it's coming. He had a really good training camp.

"One of the reasons I give him a thumbs-up at this point: Cooper and veteran receiver Michael Crabtree are making Carr better. He has developed good chemistry with both receivers, and it is helping his progression, although he does need to learn from Sunday night's follies."

This is not the first time Williamson has mentioned the developing chemistry between Carr and his two new wide receivers. Throw in third-round rookie tight end Clive Walford and pass-catching back Roy Helu, and Carr will have an array of weapons in his second season. That's an invaluable source of help for a young quarterback.

It's true that Carr still needs to work on his downfield passing game. His 2014 average of 5.46 yards-per-pass was one of the lowest marks posted by a starting quarterback in recent memory. But the Raiders must be encouraged with the overall progress he has shown this offseason.