The procedure, which could sideline Dansby for the first week of on-field practices, is the linebacker's second hand surgery of the offseason. Dansby earlier went under the knife to address a ligament problem with his right pinkie figure. The need for the latest surgery was first reported by Jeremy Green of Scouts Inc.
Dansby, 24, likely will wear a brace to support and protect the thumb when he returns to the field.
Getting one of their top young defenders into the swing of training camp as early as possible is a priority for a quickly improving Arizona defense that statistically ranked No. 8 in the NFL in 2005. Dansby is one of several emerging standouts on the unit but, like many young players, still needs more consistency.
The former Auburn standout, who has started in 27 of his 30 appearances in his first two seasons in the league, had one of the best all-around years for any player at the position in 2005. Dansby posted 103 tackles, four sacks, three interceptions, five passes defensed and three fumble recoveries in his sophomore campaign. He returned two interceptions for touchdowns.
There were times, however, when his concentration lapsed and the Cardinals coaches want him to work harder on the mental aspects of the game. Dansby was unable to do that this spring, because he missed practice time with a hamstring injury.
Cardinals officials have acknowledged that Dansby is a youngster they have identified as a core player and would like to secure him for the long-term with a contract extension. But those discussions will wait until management is more convinced about Dansby's overall commitment to the game.
A second-round choice in the 2004 draft, Dansby has started at the strongside linebacker position, and demonstrated big-play abilities. There has been some speculation that he might move to middle linebacker in 2006, but that is not likely.
In two seasons, Dansby has 171 tackles, nine sacks, four interceptions, three forced fumbles and six fumble recoveries.
Senior writer Len Pasquarelli covers the NFL for ESPN.com.