The suspension is the second this season for Williams, who is currently on the Steelers' practice squad. He was suspended for the first four games of the 2016 season for a substance-abuse policy violation while he was a member of the Buffalo Bills, who released him on Aug. 21.
The Steelers signed Williams to their practice squad on Oct. 12. His brother, linebacker Vince Williams, is in his fourth season with the Steelers.
Williams, 23, began training camp on the Bills' active/non-football illness list after he reported to minicamp in June out of shape. His weight went as high as 261 pounds during the offseason, a league source told Schefter. Williams attributed his weight gain to his pregnant fiancée's food cravings.
A fifth-round pick by the Bills in 2015, Williams played in 11 games, starting three. He gained 517 yards on 93 carries and scored seven rushing touchdowns in addition to two receiving touchdowns.
He tied an NFL record in 2015 by scoring a touchdown in each of his first six games played in the league. New England Patriots running back Robert Edwards also scored touchdowns in his first six games as a rookie in 1998.
The news of Williams' 10-game suspension was first reported by NFL Network.
ESPN's Mike Rodak contributed to this report.