Try looking at how many pitches they've thrown--IP isn't completely reliable, as it doesn't show how many pitches thrown.
Looking at the pen:
Grilli unlikely to be available tonight (back-to-back days, threw 28 pitches yesterday)
Chavez out (22 pitches)
Venditte unavailable after throwing 33 yesterday and likely to be the corresponding move to AAA for Diamond.
Osuna has not pitched Saturday and Sunday (likely rest)
Based on this, the pen is down to Osuna, Biagini, Loup, Storen, Floyd tonight.. hence why the Jays are bringing up Diamond to be insurance in case Dickey or Stroman struggle.