The suspension covers Minnesota's final three regular-season games and first playoff game. The NFL does not specify the substances for which players test positive.
A message was left seeking comment from Henderson's agent, Brian Mackler.
The Vikings were off Tuesday and unavailable for comment.
Henderson is the younger brother of linebacker E.J. Henderson, who broke his left leg Dec. 6 and is out indefinitely. Both attended Aberdeen and Maryland.
Erin Henderson has been active for only two games this season, including Sunday's win over the Cincinnati Bengals. He has played primarily on special teams since signing as an undrafted free agent in 2008.
BROWNS: : Former Seahawks and Packers coach Mike Holmgren spent his second day meeting with team owner Randy Lerner about running the team's football operations.
Holmgren, 61, who has appeared in 12 postseasons and three Super Bowls as a head coach, arrived Monday after being invited by Lerner, who wants to hire a proven executive. The two met and had dinner with associates. Holmgren was back at the team's facility in Berea, Ohio, on Tuesday along with agent Bob LaMonte.
The length of Holmgren's stay - and LaMonte's inclusion - points to his strong interest in taking over the Browns, who have struggled since returning to the league in 1999. Cleveland has had two winning seasons and one playoff appearance in 11 years.
REDSKINS: : The NFL determined it "cannot conclude" that the team committed a tampering violation before signing defensive tackle Albert Haynesworth last offseason.
In other news, running back Clinton Portis is confident he will return from the concussion that ended his season early.
"I don't think for one second this could be career-ending," he said.
RAVENS: : Running back Ray Rice, who had 13 carries for 166 yards and one touchdown in a 48-3 win Sunday over the Lions, is among three finalists for the FedEx Ground NFL Player of the Week. Fans can vote on NFL.com/FedEx through noon Friday.
MONDAY NIGHT'S SUMMARY
0 0 3 6- 9
10 7 0 7-24
SF-V.Davis 5 pass from A.Smith (Nedney kick), 3:53.
SF-FG Nedney 37, :33.
SF-Crabtree 35 pass from A.Smith (Nedney kick), :52.
Ari-FG Rackers 48, 5:46.
Ari-B.Wells 1 run (kick blocked), 14:03.
SF-Gore 2 run (Nedney kick), 9:22.
First downs 11 18
Total net yards 245 327
Rushes-Yards 18-85 36-189
Passing 160 138
Punt returns 2-(-3) 3-9
Kickoff returns 5-116 3-33
Int.-Ret. 2-10 2-4
Cmp.-Att.-Int. 16-29-2 19-35-2
Sacked-Yds. lost 4-18 1-6
Punts 4-43.8 5-41.2
Fumbles-Lost 7-5 1-0
Penalties-Yds. 11-78 7-55
Time of poss. 23:15 36:45
Rushing-Arizona, B.Wells 15-79, Hightower 2-3, Stephens-Howling 1-3. San Francisco, Gore 25-167, Coffee 6-16, Norris 1-4, A.Smith 4-2.
Passing-Arizona, Warner 16-29-2-178. San Francisco, A.Smith 19-35-2-144.
Receiving-Arizona, Boldin 5-40, Stephens-Howling 3-23, Doucet 2-41, Fitzgerald 2-22, Hightower 2-13, B.Wells 1-24, Breaston 1-15. San Francisco, Crabtree 5-67, V.Davis 3-34, Morgan 3-14, Gore 2-10, Norris 2-6, J.Hill 1-10, Coffee 1-7, Walker 1-2, A.Smith 1-(minus 6).
Missed field goals-San Francisco, Nedney 53 (WR).