Lilly has been a hot pickup as of late, and I don’t blame you given his 1.79 ERA and 5-0 record. But be wary as his ERA is not indicative of how he’s truly been pitching. He sports an xFIP of 4.33 since he’s only given up two home runs in 45.1 innings
A pitcher like Lilly is easier to predict since he has such a long track record in the majors. The larger the sample size, the easier it is to predict his future regression. Perhaps the most concerning thing should be that his strikeout rate has fallen below his career average while his walk rate has actually risen above it. Lilly is only striking out 5.56 batters per nine innings, well below the 7.64 he has averaged throughout his career.
With fewer strikeouts, this means there are more balls being hit into play. While Lilly carries a career BABIP against of .268, this year it’s sitting at .189. This is likely to increase as the season wears on.
He’s throwing roughly the same percentage of pitches as he has throughout his career, so there’s no reason to expect his results would be this different from his career averages.
It’s possible that Lilly will continue his success for a few weeks, but I’d expect his numbers to start to regress sooner rather than later. ZiPs which does player projections using sabermetrics, currently projects Lilly’s ERA for the rest of the season to be 3.69 while compiling an 8-7 record.
Try to sell him now while he’s looking like a potential ace rather than later when he’s just another guy on your staff.