Ross Township detective Brian Kohlhepp said traffic officer Sean Stafiej pulled over a Camaro operated by Bell around 1:30 p.m. after Stafiej, who was on a motorcycle, noticed a strong odor of marijuana coming from the vehicle.
Stafiej found a 20 gram bag of marijuana inside the car. Bell, Blount and a female passenger all claimed ownership of the marijuana according to police.
Bell, 22, was taken to a hospital to have blood drawn and is expected to be charged with driving under the influence of marijuana.
Bell, Blount and the female passenger were arrested and released. All three are expected to receive notice of formal charges through the mail said Kohlhepp. The possession and DUI charges are both misdemeanors.
The Steelers play a preseason game in Philadelphia on Thursday. Bell and Blount, signed as a free agent in the offseason, were expected to see significant playing time in the main tuneup for starters before Pittsburgh's Sept. 7 opener against Cleveland.
''We are aware of the reports and still gathering information,'' Steelers spokesman Burt Lauten said. ''We will have no further comment at this time.''
Bell set a franchise record for total yards by a rookie running back last season, smashing the mark set by Hall of Famer Franco Harris.
The second-round pick out of Michigan State ran for 860 yards and eight touchdowns and caught 45 passes for 399 yards despite missing the first three games of the season with a foot injury.
Pittsburgh plans to use Bell and Blount as a one-two punch, with the burly 27-year-old Blount expected to be featured heavily in short-yardage situations. The Steelers finished tied for 27th in the league with 1,383 yards rushing in 2013 on their way to an 8-8 record.
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