DETROIT - The Detroit Lions have a host of issues at running back.
Starter Jahvid Best is out with a concussion, and ESPN reported Thursday that backup. The network based its reported on two NFL sources it did not identify.
The Lions tried to trade Harrison to Philadelphia on Tuesday, but the deal was voided for unspecified reasons. The Lions listed Harrison as having an "illness" that held him out of Thursday's practice.
"It's a privacy issue and I'm not going to comment on it," Lions coach Jim Schwartz said. "He's back on our 53-man roster."
Harrison's agent, Mitch Frankel, did not return phone and email messages.
Detroit wanted to trade Harrison to Philadelphia for Ronnie Brown and a draft pick because it needs help in the backfield following Best's third concussion last Sunday in a loss to San Francisco.
Schwartz will only say that Best will play when he's given medical clearance. Lions offensive coordinator Scott Linehan said he "certainly" expects the speedy, second-year pro to be on the field again this season and Best's agent, Tony Fleming, said his client's status will be evaluated on a week-to-week basis.
"Caution is being taken of course, but he should be OK soon," Fleming wrote in an email to The Associated Press.
However, CBSSports.com's Mike Freeman reported on Wednesday that "people close to (Best) are expressing concern to him that he needs to strongly consider sitting out the year."
In any event, the Lions (5-1) are expected to rotate Maurice Morris and Keiland Williams along with return specialist Stefan Logan in the backfield against Atlanta (3-3) on Sunday at home.
"All our backs are a little bit different, all of them bring a little something different to the offense," Schwartz said. "We'll use anybody that we have available on Sunday to the best of their abilities."
Morris had five rushing attempts against the 49ers to more than double the number of carries he had over the first five games of the season. The 10-year veteran insisted he is not fired up about getting a chance to play much more against the Falcons.
"I'd be excited if I'm in one, two or three plays," Morris said. "I understand with the injury, I'm going to play more, but I approach every game the same as though I'm going to have to play a lot because you never know when somebody is going to go down and your number is going to get called. I'm preparing for this game the same way I did going into Week 1."
Morris was slowed in training camp by a broken right hand and had just two carries in the season-opening win at Tampa Bay. He had a mere two more carries over the next four games, but has been relatively productive when given a chance to do more.
The former Seattle Seahawk has had at least 15 carries four times in his two-plus seasons with the Lions and responded with 126 yards rushing and a touchdown in one of those games two years ago against Arizona and 109 yards with a score in another such opportunity last year against Tampa Bay.
Linehan doesn't expect the Falcons to overlook Morris, thinking they caught a break not having to chase Best.
"Mo has been in the League a long time, I'm sure they are going to look and say, `Hey, this guy can do this, you better not fall asleep on him,"' Linehan said.