Was there ever an episode of the 87 series where a turtle sat out the whole episode?
 

I don't have the best memory and the time/effort/access to all of the episodes... was there ever a single episode where any Turtle didn't make a single appearance?

Nope. They all appeared every single episode.

Yep.

I remember playing with my 2k3 Turtle action figures when I was a kid and once "making a few episodes" without Leo and Mike. I think I even had Don and Raph believe they had died in an explosion.

Thanks bunches!

Sorry, ten seasons, all 4 turtles.

I'm tempted to mention "The Mutagen Monster" or "The Ninja Sword of Nowhere" because the replacement actors for Donatello and Raphael sound so off that they might as well have just let the characters take the day off.

In the 2k3 series certain turtles were absent during the Season 5-7 era. I know for a fact in the second to last episode with Raph/Mikey fighting over that green mantle cape that the other turtles aren't in it.

In the season 4 episode Dragons Brewing, only Leo was there, the other 3 turtles weren't in the episode.

The clue is in the title. ;)

I'm pretty sure that the same applies to the Nick series too. I don't remember any episode with any of the turtles missing.

Shredderville, there. All 4 turtles sat out in this one, because they spend a good part of the episode asleep. They didn't do anything expect sleep.