Jones has a troubling injury history since the Cowboys drafted him in the 2008 first round. He has missed 16 games in his career because of hamstring, toe, knee and ankle injuries.
If Jones is unavailable Saturday, Sammy Morris, a 12-year veteran who was signed after DeMarco Murray was placed on injured reserve last week, is the only other tailback on the roster. Morris, who had been out of the league since being cut by the New England Patriots at the end of preseason, carried 12 times for 53 yards in his Dallas debut last week.
"Sammy is the most logical choice, so he got a lot of the work (Tuesday), and we have another young back on our practice roster (Washington), so he'll get a chance to do some of that too," Garrett said.
Morris was home in New England when he got a call last week from the Cowboys and Garrett, his former teammate and coach in Miami. Morris had been working out, but hadn't played since being cut by the Patriots at the end of training camp after playing there the last four seasons.
"Everything is kind of getting reintroduced, first day out here at practice was just getting used to running around and cutting, I guess as far as like reacting to somebody to cut, then it was on game day actually putting on pads," Morris said Tuesday. "The soreness was next, so I've got to work my way through it and get back out there."
Asked what he expected his role to be if Jones isn't able to go, Morris insisted it will be the same as last week in Tampa Bay.
"Help the team win. It's not really complicated," Morris said. "Whether it's five carries, or 25, it's help the team win."
In the first game after Murray suffered a fractured ankle, Jones matched a career high with 22 carries for 108 yards in last week's win over the Tampa Bay Buccaneers. He needed an IV at halftime and suffered from cramps toward the end of the game, which is why Morris got the majority of the work in the fourth quarter.
"I'm just looking forward to doing my part to help the team win, to make a run at the playoffs," Morris said. "It's a crucial time of the year."
Outside linebacker DeMarcus Ware (stinger) and nose tackle Jay Ratliff (rib muscle strain) also did not practice Tuesday. They rested during the second half of the Cowboys' win last week, but the pair of Pro Bowlers is expected to play against the Eagles.
Tim MacMahon covers the Cowboys for ESPNDallas.com. Information from The Associated Press was used in this report.