We have to go back two starts for one where he gave up less than 4 (7 IP, 2 ER).
As someone who relies on a certain level of metrics (K, BB, LOB rates, BABIP, etc) but is a little out of depth in terms of looking at actual pitch level performance (velocity, pitch grades, etc), the numbers are concerning because he just stopped striking people out. BABIP is normal, LOB rate is fine, he just stopped putting people away. He pitched like a top 15 guy through like August 15th (10th in fWAR through that date, 6th in ERA, 25th in xFIP), and now YTD he's 15th in fWAR, 13th in ERA, 34th in xFIP. I think that overall numbers are pretty indicative of who he is, a good not great starter. But Jameson Taillon is probably bad. He's not pitching strong, he's overly reliant on defense. He has the fifth lowest BABIP of anyone with over 110 innings and he's barely holding onto a sub-4.00 ERA.