You are probably on to something here. Taking a look at last year’s result for relief pitching from August 11 on, the Tigers had the lowest BABIP (.230) by over 20 points; the second highest LOB% (78.0%); and were 8th in lowest HR/FB (8.3%). All are markers of luck, which helped lead to us having by far the highest RA9-WAR (the results-based WAR) with 6.5, far ahead of Cleveland and Milwaukee, who were tied for second with a mere 4.0.
That said, the Tigers were also #2 in regular WAR (the process-based WAR) with 3.3, behind only Milwaukee at 3.6. We achieved this because while we were #30 of 30 in relief pitcher strikeout rate after 8/11, we were also tops in walk rate and #7 in HR rate. This led to us being 5th in FIP, even though we were 13th in xFIP (the quality of contact FIP).
TL;DR: even though we did get quite lucky with the results from our relievers after 8/11 last year, we were also very good underneath the hood.
BTW: in the second half of this year, our RA9-WAR from relievers is 2.2, 6th-best in baseball, even though our regular WAR is 21st at 0.3. That’s because we’ve been 3rd in BABIP and 4th in LOB. Either we’ve been nothing but lucky in this way for two years in a row, or there’s something we have that makes this happen—maybe defense?