Sources told ESPN.com that Lawson was late to a Kings shootaround in Las Vegas earlier this week, then missed the team's trip east before Saturday night's Sacramento/Washington preseason game at the University of Kentucky's Rupp Arena, which represented a homecoming of sorts for Kings star DeMarcus Cousins and Wizards counterpart John Wall.
The Kings attributed Lawson's absence from the lineup in Lexington to "personal reasons." He has since returned to Sacramento, sources said, and faces an uncertain future with his new team after the week's events.
Lawson's agent, Happy Walters, couldn't be immediately reached Sunday.
Knowing it would be forced to start the season without the suspended Darren Collison, Sacramento signed Lawson on Aug. 31 to a one-year minimum deal that was non-guaranteed, hopeful that the former Denver Nuggets fixture would seize the opportunity to resurrect his career and fill a void in their backcourt.
But Collison was ultimately suspended for just the first eight games of the regular season after a misdemeanor conviction for domestic assault. The Kings signed Lawson only after considerable internal deliberation after the veteran guard's history of legal woes, so it remains to be seen how much patience they'll show.
Sacramento also recently signed veteran point guard Jordan Farmar, who played in Memphis last season under new Kings coach Dave Joerger, to help them cope with Collison's absence.
The Kings have been publicly optimistic about Lawson's ability to contribute for much of training camp, with Joerger praising Lawson's defense in a recent exhibition outing against Golden State's Stephen Curry and saying: "He has good leadership qualities. You can tell why he's been a winner."
Lawson, 28, has been arrested four times for driving under the influence -- twice in a seven-month span in 2015. He didn't last a full season with the Houston Rockets in 2015-16 before his March release; he finished last season with the Indiana Pacers.
Through his first six seasons, Lawson was a key member of the Nuggets, earning a contract extension in 2013 that was $4 million richer than Curry's four-year, $44 million deal that expires after this season.
In a July interview with The Undefeated's Marc J. Spears, Lawson said: "It would be big to be back to my old self again. Also, it's not for just me, it's for my parents. They have had a hard time seeing what I've been going through. I know they hear the little comments at NBA games. To make them proud again would mean the world to me."