Lyles was a late scratch from Saturday's start against the Giants for unknown reasons, Andrew Baggarly of The Athletic Bay Area reports.
Lyles was assumed to be Saturday's starting pitcher until Matt Strahm came in to warm up in the first inning. It's not yet clear why Lyles was removed, but Strahm was given extra time to warm up, which means he was sent into the game as an injury or illness replacement rather than a strategic change.