Mesoraco was hit on Saturday during a spring training game against Kansas City and was held out of a game the following day. Mesoraco said on Monday that it's a mild concussion and has left him a little hazy.
He's being tested daily and is confined to riding a stationary bicycle and walking on a treadmill to stay in shape.
"It is tough for me to sit around, but that's what you have to do," Mesoraco said. "Right now I want to get back to work and I can't do it. I did 20 minutes on the bike today. Tomorrow, I'll walk on the treadmill."
It's his third concussion as a professional. The other two came on collisions at home plate. Mesoraco says this one isn't as bad as the others, which happened in 2010 and 2012. It's unclear when he'll be allowed to resume a full range of activities.
"This was different than the first two," Mesoraco said. "I had more headaches the last time. With this one everything is just hazy."
He's considering changing his equipment to protect against another concussion.
"We may try a heavier-grade mask," Mesoraco said. "We will maybe put some stuff in my helmet."