Two highly regarded college defensive prospects will enter this week's NFL draft with red flags.
Multiple sources told FOXSports.com that Georgia outside linebacker/defensive end Justin Houston and Iowa defensive lineman Christian Ballard failed drug tests at the NFL Scouting Combine in February. Both players tested positive for marijuana, the sources said.
Houston, an early entry junior, is projected in some mock drafts as a late first-round draft choice. The 6-foot-3, 270-pound Houston had 67 tackles and 10 sacks last season for the Bulldogs as a rush linebacker.
Houston's athleticism and pass-rush skills make him especially appealing as an outside linebacker for NFL teams that use a 3-4 defensive scheme.
The 6-foot-4, 283-pound Ballard was projected by some draft analysts to get selected as early as the second round. Ballard played at both end and tackle in 13 starts for the Hawkeyes last season, tallying 43 tackles and three sacks. Ballard notched at least 40 tackles in each of his past three seasons at Iowa. Ballard's wing span and athleticism have made him an intriguing draft prospect.
Houston and Ballard have clean police records and no known history of marijuana use.
The agents for Houston and Ballard didn't return telephone calls or emails seeking comment.
The NFL draft will take place Thursday through Saturday in New York City.