"He had a migraine this morning, so they scratched him and put Mastro in there," Antony said. "He's had some issues [in the past], but it's just one of those things where every once in a while he gets one. But I'm not sure what causes it."
Kepler, 23 and the Twins' 2015 Minor League Player of the Year, is competing for a spot in the outfield but is expected to open the year at Triple-A Rochester. The Twins, though, still haven't sent him to Minor League camp, as they want to continue to get a good look at him. Kepler, who was also the Southern League MVP with Double-A Chattanooga last year, is hitting .250 with two RBIs and a stolen base in 12 games this spring.
"I like watching Max play," manager Paul Molitor said. "He's learning up here. We've kept him around because that's one position [center field] we haven't really cemented in. I'm trying to get him as much experience in camp as I can, to see where he's at."
• The Twins are set to unveil the fan safety netting at Target Field to the media on Wednesday. Team president Dave St. Peter and senior vice president of operations Matt Hoy will be in attendance. The club is installing netting behind home plate that is easier to see through as well as a six-foot net above both dugouts.
• The Twins released several Minor Leaguers, including right-hander Brandon Poulson, whose story went national when the Twins signed him for $250,000 out of the Academy of Art University in 2014. Poulson, 26, posted a 3.10 ERA with 26 strikeouts and 19 walks in 20 1/3 innings in the Gulf Coast League last year. The Twins didn't feel he threw enough strikes to succeed and saw his velocity decrease as he tried to improve his control.
• GM Terry Ryan and Molitor are expected to meet after Tuesday's split-squad action to talk about the next round of roster cuts, which could come as soon as Wednesday.
Rhett Bollinger is a reporter for MLB.com. Read his blog, Bollinger Beat, follow him on Twitter @RhettBollinger and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.