Situation: Batter hits ball and reaches base safely. R1 moves from 1st to 3rd and rounds 3rd. Ball is thrown to catcher and runner stops, not on the base. Catcher moves toward R1 but runner does not return to base. Catcher calls time, umpire does not suspend play.

Is that because the umpire judged the play to be in progress and 5.10 (h) applies. "Except in the cases stated in paragraphs (b) and (c) (1) of this rule, no umpire shall call "Time" while a play is in progress."

Is there anyplace that says when a play is no longer in progress, such as when the lead runner has returned to his base?

Your ruling sounds correct to me.
I wouldn't grant time either, until
the ball gets back to the pitcher
(and prbably not then, either, unless
catcher has to fix gear or something).

I had a kid in left field back up an over-
throw to 3B with runner on 3rd. He's out
there calling time, finally threw in to
pitcher. I told him I wouldn't grant time
while the ball was still live in the
outfield. I notice they allow that in
softball (time when infielder has ball).

If umpires stopped granting "time" so often
(like hand up with batter in box, and
every time a runner hits the dirt on a
pick off play) the game wouldn't drag so much.
Just my pet peeve.

"I notice they allow that in
softball (time when infielder has ball)."

Better qualify that statement. That's in slo-pitch, NOT in fast pitch.

Bob

I notice that they allow that
in slo-pitch softball.

Years ago I had a boys' jr. var. game and during the top of the first the infielders wanted timeout as soon as the ball got back into the infield from the outfield. I told them that this was baseball not slow pitch softball. That ended their requests for timeouts all of the time.