The Blue Jay outfielder sneezed on Saturday and felt a sharp pain in his right side.
He didn't want to tell the trainers about it, but it turns out he has a Grade-1 oblique strain and he’s been advised to rest.
"I don’t think this is a big deal," Pillar said Sunday. "It's something I played with (Saturday) and something I was prepared with to play today. But they're being very respectful about it and willing to give me a little bit of time."
The Jays don't start the regular season until April 6, so Pillar should have plenty of time to recover by then.
Pillar is not the first Blue Jay to suffer an oblique injury from sneezing.
The same thing happened to Ricky Romero back in 2009.
After an MRI confirmed he had a strained oblique, Romero then told reporters that the episode had left him afraid to sneeze.