My first post on this was Astros Offense On Record Setting Low Pace. Right now their OPS is .663 and the league average is .727. So .663/.72 = .912, giving them a relative OPS of about 91. That would put them in the bottom 25 since 1993.
The Astros have an OPS+ of 78 according to Baseball Reference. It takes park effects into effect as well as the league average (it is calculated a little differently than above). That is last in the NL this year. The Pirates are next lowest at 81. The lowest team OPS+ I found going all the way back to 1920 was 69 for the 1920 Philadelphia A's. But the Mariners are even lower now than the Astros with a 77. The last time any team finished a season below 80 was in 2004, the Expos (78) and the Diamondbacks (77).
The Blue Jays have an isolated power (ISO) of .205 since their SLG is .455 and their AVG is .250. That is about the same as the all-time record of .205 by the 1997 Mariners. Relative to the league average, it would be the 6th highest since 1900, at 139 (.205/.148 = 1.39). The league ISO in the AL this year is .148. The 1927 Yankees are the highest in relative ISO at 153. The Jays ISO is .233 at home and .180 on the road.
My first post on this was Blue Jays On Record Power Pace.