The Cardinals are exploring the possibility of trading for 49ers quarterback Alex Smith, according to an NFL source, but no deal is in place.

It’s unknown how serious the Cardinals are about trading for a quarterback for the second time in less than two years. But they are intrigued by Smith’s experience, intelligence and talents, according to the source. They believe much of his struggles early in his career can be attributed to changes in coaches and offensive systems.

The Cardinals are looking into all options to improve production at the position. That includes bringing back Kevin Kolb at a reduced salary. It’s unknown if those discussions have started. They also are likely to draft a quarterback in the first three rounds.

The Cardinals traded for Kolb in the summer of 2011 and have paid him $20 million. He’s due a bonus of $2 million if he’s on the roster March 17 and his salary for this year is scheduled to be $9 million.

Jason LaCanfora of CBS reported this week the 49ers have told others that a deal for Smith is “effectively complete.” Several other reports, including one from the Sacramento Bee, quoting league sources, reported that the 49ers were still talking to teams about a trade and that no deal was in place.

A handful of teams might have interest in Smith, according to reports, including the Chiefs, Cardinals, Browns and Jaguars.

It makes little sense for the 49ers to narrow their trade options at this point. Teams can discuss trades now but no deal can be signed until March 12, the beginning of the 2013 league year. The 49ers might be confident they can trade Smith, but it’s questionable why they wouldn’t take all available time to make the best possible deal.

The 49ers owe Smith a bonus of $1 million if he’s on the roster on March 15. On April 1, his $8.5 million salary becomes guaranteed.