After Rays starter Alex Cobb took a liner off the head Saturday, suffering a mild concussion, Jackson acknowledged those type of plays can be difficult to avoid.
"Sometimes there isn't so much you can do. You see a lot of times the catches people make, they throw the glove up there. It's just one of those unfortunate parts of the game," Jackson said on Sunday. "Sometimes balls come back at you. Sometimes you can get out of the way, sometimes you can't. I don't really play the game thinking about it. I know it can happen just as easy as someone can throw a ball and hit a batter in the head. It's one of those unfortunate things."
Jackson can still recall the exact details of when he was hit in the back of the head -- a liner by Adam Lind on an inside fastball in a road game at Toronto -- but said he hasn't thought about it too much after it happened on Sept. 16, 2006.
Cobb is the second pitcher to be in the head with a line drive this year, as Toronto's J.A. Happ also took a ball off the head. Cubs manager Dale Sveum isn't sure if there's a way to better protect pitchers.
"I don't know if a pitcher could possibly pitch with a helmet on -- that's what you're talking about. Or some kind of hard shell underneath the hat, like the old days. You're not going to cover up faces, a guy has to pitch. I don't know if there's really anything you can possibly do," Sveum said. "It's obviously a dangerous thing to be that close to a major league hitter hitting a line drive."
Evaluating Garza: In his first five starts since returning from a lat strain, Matt Garza is just 1-1 with a 6.26 ERA. The high ERA is largely due to a five-inning, nine-run outing last time out against Cincinnati. Sveum said Garza hasn't mastered his fastball command since coming off the disabled list in late May.
"That's where it all starts, fastball command," Sveum said. " Keeping the ball down in his case. He's capable of pitching to both sides of the plate, but he's just not getting the ball down enough in the strike zone with his fastball."
Garza could be a player the Cubs look to move at the trade deadline. Sveum said it would be hard to lose a pitcher of Garza's caliber.
Position call-up: When outfielder David DeJesus (shoulder) was placed on the disabled list on Saturday, the Cubs called up reliever Shawn Camp, leaving them short a position player while fortifying a taxed bullpen.
Sveum said the bullpen is now fine with its workload, and the lack of positional players shouldn't be an issue for a couple more days. He said the team benefits from its pitchers being able to handle their at-bats.
"Right now we're OK," Sveum said. "Obviously we're going to evaluate it and make a decision."
DeJesus flew ahead to Chicago on Sunday in preparation for his MRI.