CINCINNATI -- A scary head-to-head collision forced Reds left fielder Chris Dickerson to make an early exit from Monday's game vs. the Astros.
Dickerson, who was later diagnosed with "concussion-like symptoms," was replaced before the sixth inning by Laynce Nix.
"Everything was real spotty. It was like going from HD to regular television," Dickerson said after the Reds' 4-1 loss to Houston.
On first base with a single in the bottom of the fourth inning, Dickerson was sliding into second base to break up a potential double play after Joey Votto's grounder to first base.
Shortstop Miguel Tejada dropped first baseman Lance Berkman's throw for the force play and fell forward, and Dickerson came in hard at second. Tejada bumped heads with Dickerson, who lost his helmet on the collision.
Both players were shaken up on the play and required attention from their respective trainers and managers, delaying the game for a few minutes.
Tejada stayed in the game, going 3-for-4 on the night and scoring a run in the ninth.
"I thought I was OK," Dickerson said. "I was standing at second trying to focus on smaller things, the back stop. It was tough [but] something I thought was going to go away. I didn't know it would escalate to the degree that it was when I got back out to the outfield."
Dickerson, who has suffered multiple concussions over the years, including one when he was in fifth grade, did not require a trip to the hospital. The 27-year-old was examined at Great American Ball Park by a doctor. He will undergo more testing on Tuesday.
"I'm doing all right," Dickerson said. "My vision is coming back a little bit. Right now, I feel a little drowsy. I just want to sleep. It's not as hard to focus, which is a good sign. I just had to answer simple questions like, 'What happened yesterday?' It almost took me a while to answer, but I got it."
Dickerson's single in the fourth snapped an 0-for-10 streak. In 17 games, he is batting .205 with one home run and five RBIs.
Mark Sheldon is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.