Furyk will name his final pick on Monday, following this weekend's penultimate PGA Tour event, the BMW Championship.
DeChambeau, who has never played in the biennial event, finished ninth on the list, while fourteen-time major victor Tiger Woods is also likely to be included.
Mickelson and Woods were considered virtual locks, with both Ryder Cup veterans playing well enough throughout the summer to warrant spots on the team.
The United States' Ryder Cup team held a press conference today at the Philadelphia Marriott West in West Conshohocken to announce three of U.S. Captain Jim Furyk's captain's picks.
DeChambeau, who rose to the top of the FedEx Cup standings with a win last week in New Jersey, further distanced himself from the pack with another success - his third of the year.
Serena Williams progresses to US Open quarterfinals
She hasn't won since and is trying to avoid going without a Grand Slam for the first year since 2011. Her victory came a day after daughter Olympia turned one year old.
Norton, Mass. • Bryson DeChambeau has found the right formula for the richest part of the PGA Tour season.
Furyk will announce his final captain's pick next Monday to complete the 12-man team.
Woods, 42, said he wouldn't object to partnering with him in foursomes (alternate shot) and four-ball (best-ball) formats in the US Ryder Cup showdown with Europe on September 28-30 at France's Le Golf National.
"Bryson was fantastic to play with", Woods said.
Tony Finau is believed to be the leading candidate for 12th and final spot.
Petrol price hits a record high in Mumbai
The US sanctions on Iran is not the only reason for India to be anxious about a possible spike in petrol and diesel prices. Fuel prices have been on the rise since August 16 after the rupee dipped to its lowest value against the USA dollar.
That seemed like a pipe dream, but as Woods played and quickly began contending in tournaments, it began to look like a reality and was cemented by his runner-up finish at the PGA in August. Pieters endured a slow start to the year but hasn't missed a cut since May, picking up three top-tens in his last five starts alone.
The eight automatic qualifiers were Brooks Koepka, Dustin Johnson, Justin Thomas, Patrick Reed, Bubba Watson, Jordan Spieth, Rickie Fowler and Webb Simpson. "How much? I would say it depends on what I can do in the restrictions of my biomechanics".
The bookmakers have had their work cut out in pricing up the odds for Thomas Bjorn's potential wildcard picks for the European Ryder Cup team to take on U.S. later this month.
Watch Thomas Bjorn complete his European Ryder Cup side in a special announcement show, live on Wednesday from 2pm on Sky Sports Golf.
RAW: Brazil's largest museum burning in massive blaze
After two adjacent hydrants were found to be dry, water trucks, with water from nearby lakes, had to be brought in. It houses several landmark collections including Egyptian artefacts and the oldest human fossil found in Brazil.
Woods will no longer be a vice captain, though Furyk said he would continue to lean on his advice.