It should mean becoming a player, but the NFHS didn't write the rules that way, so it actually means to be on the court during a live ball. Being beckoned in and becoming a player is not enough.
3.5.6 SITUATION A:
Substitute A6 is beckoned and enters the court to replace
A1. A6 is wearing: (a) compression shorts below the game pants which extend
below the knees; (b) cut-off jeans extending below the game pants; or (c) jewelry.
RULING:
The items in (a), (b) and (c) are illegal and A6 will not be allowed to
participate while wearing the items. No penalty is involved. A6 simply cannot
participate until the illegal items are removed. (3-5-7)
3.6.1 SITUATION:
A6 enters the game with an excessive manufacturer’s or
school’s logo on his/her: (a) socks; or (b) wristbands. RULING: Legal in (a). In
(b), A6 may not participate and is directed to return to the bench until legally
equipped. COMMENT: The restriction on visible manufacturer’s or school’s logo
size is in effect on pants/skirts, compression shorts, wristbands and headbands.
The shoes and socks are not considered part of the uniform for purpose of visible
logo size.
4.34.3 SITUATION:
Substitute A6 reports to the scorer to replace player A1 and
awaits entry to the game. The U2 beckons A6 onto the court, and (a) A6 enters
the court to participate; (b) A6 enters the court and commits an unsporting, noncontact
foul; or (c) A1 swears at the official while heading to the bench. RULING:
A6 became a player upon being beckoned by the official and entering the court.
Legal in (a). In (b) A6, now a player, is penalized with a technical foul which is
added to the team foul total. In (c) A1, now bench personnel, is penalized with a
technical foul, which is added to the team foul total and also charged as an indirect
technical foul to the head coach.
10.5.3 SITUATION:
A5 has just received his/her fifth foul of the game. A5 (a) is
erroneously permitted to remain in the game for another two minutes before the
scorer realizes the mistake; or (b) leaves the game after the coach is notified of
the disqualification. At the intermission between the third and fourth quarter, A5
reports as a substitute and subsequently enters the game. RULING: In (a), as
soon as the error is discovered, the player is removed from the game, no penalties
are assessed. In (b), A5 will not actually "participate" until the ball becomes
live. If detected prior to the ball becoming live, A5 would be directed to the bench
and no penalty assessed unless the official deemed it was a deliberate attempt to
circumvent the rules. If detected after the ball becomes live, it is a technical foul
charged directly to the head coach. The player is immediately removed from the
game and Team B is awarded two free throws and the ball. (2-11-5 Note 2)