Red Sox/Blue Jays 6.10 Question

[rulesmaven]

My second question in a week -- hope I'm not overstaying my welcome.

Was watching Red Sox v. Blue Jays tonight with friends. David Ortiz was the DH on the lineup card. He had back spasms and did not take his first at bat against the starting pitcher. Instead another player (Lowrie) took the on deck cicle and was announced as, and batted as, a pinch hitter. He played the rest of the game as the DH.

One of the people watching the game mentioned he thought the DH had to take an at bat and that sounded familiar. Looking at OBR 6.10(b), it says that the line up card DH must "come to bat" at least once unless the pitcher has changed. Does this mean actually take the batter's box, or is this merely a rule to ensure the DH cannot re-enter the game and must sit out if he doesn't take his first at bat -- that is he cannot be a substitute later?

If the former, what should the penalty have been? None is stated in the rule. Is it an out of order appeal play?

If the latter, does that mean a DH doesn't enter the game until he bats, even if he's on the lineup card? (I guess the only time this would matter is this: Jones on lineup card as DH. Before his first AB, opponent brings in a new pitcher. Can Smith now be DH and Jones pinch run or pinch hit later?). Just curiuos. Thanks.