Howard is still experiencing back spasms Wednesday and won't throw over the next few days, Todd Zolecki of MLB.com reports.
Howard was scratched from his scheduled Grapefruit League appearance Monday due to back spasms, and the right-hander is still working through the issue. Howard had looked good to begin spring training and displayed improved velocity and conditioning, but he could be excluded from the Opening Day roster if he isn't ready in time for the regular season. Although Howard could be forced to work out of the bullpen after the Phillies acquired Matt Moore and Chase Anderson during the offseason, the 24-year-old should be one of the team's top options to fill in as a starter once he's fully healthy.