Key NBA Champion named Mavericks' best free-agent signing

"Though Shawn Marion may not feel like a free-agent addition since he arrived as part of a four-team trade, that July 2009 deal was indeed a sign-and-trade, which allows him to be included here.

"The veteran glue guy was arguably the last piece Dallas needed to become champions in 2011.

"Marion averaged 11.6 points, 7.0 rebounds and 1.8 assists per game over his five seasons in Dallas, but most of his greatest contributions aren't the kinds of things that show up on the stat sheet. He was versatile both on the court and in the rotation, including coming off the bench for most of the 2010-2011 season. Marion excelled at doing the dirty work, particularly on the defensive end where he soaked up big minutes often against some of the toughest assignments.

"When needed, Marion could get buckets, but he was also both willing and able to defer to Dallas' primary weapons, notably Dirk Nowitzki.

"Sometimes, a team needs a first-option star to get to the mountaintop. In Dallas' case, it needed a player like Marion—a reliable, gritty veteran who would do whatever it took to help the team win."

Looking back on that sign-and-trade is pretty eye-opening. Marion had been traded to the Toronto Raptors just months prior, and all the Mavs had to give up, besides agreeing to a contract with him, were a 35-year-old Jerry Stackhouse, a 32-year-old Devean George, Antoine Wright (who never did much in the NBA), and cash. Giving up that for a key starter on an NBA championship team in 2011 is a bargain.