Howard was transferred to the Phillies' alternate training site at Lehigh Valley on Tuesday, Meghan Montemurro of The Athletic reports.
The 23-year-old was competing for a back-end spot in the starting rotation, but he won't be on the 30-man roster to begin the season. Howard put on a strong performance in summer camp and finished by allowing one run on one hit and two walks while striking out four over four innings during Tuesday's intrasquad game. Pitching coach Bryan Price previously said Howard should be a part of the rotation early in the season, and while that still may happen, he won't be on the team's Opening Day roster.