In January 1984, Bentley was selected by the
Chicago Blitz with the seventh overall selection in the
1984 USFL draft. However, Bentley's contract negotiations with the Blitz stalled following the draft. As the 1984 USFL season got underway, the Blitz traded him to the
Michigan Panthers who were looking to replace running back
Ken Lacy after he moved to the NFL. Bentley signed with the Panthers and began his professional career in the USFL. Bentley was later selected by the
Indianapolis Colts in the second round (36th overall) of the
1984 NFL Supplemental Draft.
Michigan Panthers/Oakland Invaders (1984–1985) Bentley signed with the Michigan Panthers on April 17, 1984, following week eight of the USFL season. Bentley was used mostly as a backup running back while also returning kickoffs for the remaining 10 games of the season. Bentley recorded 18 carries for 60 yards and returned 19 kickoffs for 425 yards on the year. The Panthers went 12–6 in the regular season and lost to the
Los Angeles Express in the Divisional Round of the playoffs. In 1985, the Panthers organization merged with the
Oakland Invaders and continued playing under the Invaders name. Bentley stayed with Oakland, where he led the team with 191 rushes for 1,020 yards and four touchdowns, while adding 44 catches for 441 yards and three touchdowns. In his first year with the Colts, Bentley appeared in 15 games with 54 rushes for 288 yards and two touchdowns while returning 27 kickoffs for 674 yards and a career-high 25.0-yard average return. In week five against the
Buffalo Bills, Bentley recorded his first 100-yard rushing performance in the NFL with 17 carries for 100 yards. Bentley scored one rushing touchdown each in the final two weeks of the season against the
Tampa Bay Buccaneers and
Houston Oilers, respectively. The Colts went 4–11 on the season. In 1986, Bentley continued to serve as a backup to
Randy McMillan, splitting time throughout the season with
George Wonsley while also returning kickoffs. He recorded 73 carries for 351 yards and three touchdowns with 25 receptions for 230 yards. Bentley had 32 kick returns for 687 yards, averaging 21.5 yards per return. The Colts started the 1986 season at 0–13, firing head coach
Rod Dowhower and replacing him with
Ron Meyer. Meyer won the final three games, ending the Colts' season at 3–13. In 1987, Bentley had his best statistical season in the NFL. However, a new Colts running back and the
1987 player's strike stood in his way. The NFL canceled all week three games and used replacement players for weeks four through six. At the conclusion of the strike, the Colts traded for running back
Eric Dickerson. Bentley was Dickerson's backup for the remainder of the season, but still produced in the 12 games he appeared with 142 rushes for 631 yards and a career-high seven rushing touchdowns. He added 34 receptions for 447 yards and two touchdowns while also returning 22 kicks for 500 yards. By 1988, Dickerson was taking the majority of the snaps at running back leaving Bentley to start only two games. Dickerson led the league in rushing, and Bentley found a complimentary role in the Colts' offense. He appeared in all 16 games with 45 carries for 230 yards and two touchdowns and added 26 receptions for 252 yards and one touchdown. As a kick returner, Bentley saw his largest career workload with 39 returns for 775 yards. For the 1989 season, the Colts moved to a two-running back formation and Bentley saw an uptick in his playing time. He finished the season with 75 rushing attempts for 299 yards and one touchdown and had 52 receptions for 525 yards and three touchdowns. Bentley joined wide receivers
Andre Rison and
Bill Brooks as the first trio in Colts history to record 500 receiving yards each in one season. The Colts finished the season at 8-8. In 1990, Bentley was again productive on the ground and had his best season as a pass catcher. He posted 137 carries for 556 yards and four touchdowns and added career-highs with a team-leading 71 receptions for 664 yards and two touchdowns. For the second consecutive season, Bentley was part of a trio of Colts receivers with over 500 yards, the others being Brooks and
Jessie Hester. The Colts finished the season at 7–9. In 1991, Bentley injured his shoulder in a preseason game against the
Philadelphia Eagles. He missed week one, and upon his return in week two he suffered a knee injury against the
Miami Dolphins. Bentley was placed on injured reserve and missed the rest of the 1991 season.
Pittsburgh Steelers (1992) Bentley signed with the
Pittsburgh Steelers on September 16, 1992. Bentley returned one kickoff for 17 yards in two appearances with the Steelers before being released on November 16, 1992. ==Professional career statistics==