Austin Kearns hit a ball to the gap in deep left-center field, and both Jennings and Upton converged on the drive. Just when Upton appeared to have caught the ball, they ran into each other.
Both outfielders remained on the ground while Kearns rounded the bases for a three-run inside-the-park home run.
Once the play was completed, trainers and manager Joe Maddon rushed to the outfield to tend to the players. When Jennings and Upton got to their feet, they were picked up in a cart on the warning track. Both were sitting up as they were driven back to the Rays' clubhouse.
"We just collided," Jennings said. "We both had a bead on the ball at the same time. ... There wasn't any avoiding that one. The ball was coming back toward me with the wind bringing it back a little bit, so I figured I had a chance to get to it. He got a bead on it from the beginning. It was just a ball hit in a perfect spot. It was hard to avoid that situation."
Jennings, who was a standout high school wide receiver in Alabama, smiled when asked if the play brought back memories of catching a pass across the middle.
"[It] felt like somebody else was going across the middle," Jennings said. "No, it didn't feel good. Everything's fine. Nothing [hurts] now. It was more like it scared me moreso than it hurts. Everything feels good. [I'll] see how I feel tomorrow. I'll probably be a little sore, [but] that's it."
Upton said that Jennings heard him call for the ball at the last minute, but "it was too late."
"You know what? It was hit in the perfect spot," Upton said. "Off the bat, I had an idea that we both had a chance to get to it. We called it at the same time. You know, luckily we saw each other and were able to brace for the hit. Otherwise, we might have hit face to face. Other than that just [being] a little bit sore, [it's] no big deal."
Upton said his lower back was a little sore.
Manager Joe Maddon called it a "pretty awful looking collision."
"When I went out there, I didn't think either one of them could stay in the game at that point, so I just called for the other guys, wanted to make sure," said Maddon. "[It was] kind of a full-speed collision. The thing I appreciate -- honestly -- is how they're going after a ball in a Spring Training game.
"We've talked about that in the past, the fact that we're still playing the game the right way. You don't want to see that happen, but it's going to happen on occasion. Fortunately, both of them are all right, but we do appreciate the effort."
Bill Chastain is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.