Lyles was shelled for five runs on six hits with a strikeout while failing to escape the second inning in Thursday's spring loss to the Cubs.
Lyles is competing for one of the Padres' final two rotation spots this spring after signing a major-league deal this offseason. The 27-year-old hasn't posted an ERA below 5.00 since 2014, so he will have to turn things around quickly to have a realistic shot at making the club as a starter. If he were to secure a starting job, his value would be limited to very deep and NL-only formats.