The home side were presented with a good chance to take the lead in the sixth minute when Jalil Anibaba collected a pass from Ike Opara, but his low drive from close range was well saved by Nick Rimando.
In the second half, Sporting upped the ante as Benny Feilhaber raided down the flank and crossed to the near post for Krisztian Nemeth, but his effort clattered off the woodwork, while Jacob Peterson put the rebound wide of the target.
Dominic Dwyer thought he had put the home side ahead in the 55th minute when he latched onto a through ball from Feilhaber and poked the ball past Rimando, but his effort was disallowed for offside.
Sporting came close again when Dwyer was felled on the edge of the area, and from the resulting free kick Roger Espinoza put his strike just wide of the target.
The home side pushed for a winner late in the game, but couldn't find a breakthrough as the match ended in a stalemate.