Chasing a ball hit by Ian Kinsler, Jackson sprinted toward the warning track with his head turned backward as he ran full-steam into the right-field wall. He went down in pain, clutching his right wrist.
"It carried a lot more than I thought it was going to go," Jackson said after Sunday's 11-4 loss to the Rangers. "Usually, if you know a ball is going to go far, after about five or six steps, you're looking to see where you are, where the ball is hit and the wind takes it a little bit. Kind of don't have that luxury [at Fenway], I guess. My first day out in right field, I'm not going to hold up on a fly ball."
Jackson remained in the game to finish the third, and while he tried to loosen up by riding the bike between innings, the crash was too much for Jackson to return.
"My knee, my wrist is kind of sore; everything is kind of sore," he said. "I got some X-rays, which were negative. That's a good sign. Hopefully some treatment, and we'll be back out there."
Starting pitcher John Lackey, who allowed six earned runs and took the loss on Sunday, appreciated Jackson's tenacity, but he would rather Jackson remain unharmed than run into the wall trying to make a catch.
"He never even thought about slowing down," Lackey said. "He hit that thing hard. You appreciate the effort as a pitcher, but you don't want him running into a wall like that for you. I mean, he's going to be hurting for a couple days."
But it was Jackson's first chance to play ahead of Darnell McDonald, his primary competition in right field for the time being as the two battle for playing time against left-handed pitching.
"That's the most frustrating thing," Jackson said. "Going into [Friday], I hadn't played in about six days. Obviously, I wanted those at-bats."
Jason Mastrodonato is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.