Brad Penny won’t start against the Mets tonight because of irritation in the front of his right shoulder, but he underwent an MRI on Monday that showed no structural damage. Penny said if it were a regular season game, he would start. But manager Grady Little doesn’t want to take any chances with this being spring training. It also isn’t expected to set Penny back at all in his preparations for the season. Little said he should be ready to go seven or eight innings in his first start, which is expected to come on April 6 at San Francisco. So, no reason to panic for now.