Does Sentinel's opportunity attack trigger when I shove someone? [duplicate]

Question

Alright, so me and my pal are working through making a 5e fighty Cleric. He wants to take the Sentinel and Shield Master feats. Sentinel and Shield Master's relevant parts read:

Sentinel

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You have mastered techniques to take advantage of every drop in any enemy's guard, gaining the following benefits:

• Creatures within 5 feet of you provoke opportunity attacks from you even if they take the Disengage action before leaving your reach.

Shield Master

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You use shields not just for protection but also for offense. You gain the following benefits while you are wielding a shield:

• If you take the Attack action on your turn, you can use a bonus action to try to shove a creature within 5 feet of you with your shield.

Shoving allows you to make a Strength (Athletics) Check versus either their Strength (Athletics) or Dexterity (Acrobatics) check, and if you succeed you can either knock the target prone or push them 5 feet away.

So my buddy came up with the idea of using the Shield Master's Bonus Action to shove a creature during the Attack Action, and then taking an Opportunity Attack from the Sentinel Feat, since they left his reach (he is wielding a sword, in case that matters here).

So the so the question is: Can the Shove Action provoke Opportunity Attacks as described by the Sentinel Feat?

It just occurred to me that perhaps the Shield Master portion isn't important for the question, but perhaps it is relevant. Sentinel does describe Opportunity Attacks in a slightly different way than they are described on page 195 of the PHB.

Answer 1

No, you can't provoke opportunity attacks this way. From the Player's Basic Rules, page 74:

You also don’t provoke an opportunity attack when you teleport or when someone or something moves you without using your movement, action, or reaction. For example, you don’t provoke an opportunity attack if an explosion hurls you out of a foe’s reach or if gravity causes you to fall past an enemy.

Effectively, only voluntary movement can provoke opportunity attacks. Any method you have of pushing someone or otherwise physically forcing them to move will not provoke opportunity attacks.

If your Cleric wants to force a creature to provoke an opportunity attack from him, he should use the spell Command (or something similar) to order them to walk away from him. On their turn, when they use their movement to walk away, he will be able to make his opportunity attack as he wishes.

Answer 2

The basic rule of thumb is, When the enemy uses THEIR move action, it can provoke an attack. If their movement is done via any other method than their own action, it cannot provoke an attack of opportunity.

Answer 3

Normal opportunity of attacks, I agree would not work, but the sentinel description is vague (on purpose?) though, I would have to say some things "shouldn't" work, such as a powerful explosion or eruption of energy that throws something at considerable velocity.

You have mastered techniques to take advantage of every drop in an enemy's defense.

And then the bullets:

• When you hit a creature with an opportunity attack, the creature’s speed becomes 0 for the rest of the turn.
• Creatures provoke opportunity attacks from you even if they take the Disengage action before leaving your reach.
• When a creature within melee range of you makes an attack against a target other than you (and that target doesn’t have this feat), you can use your reaction to make a melee weapon attack against the attacking creature.

My main argument points being that it's phrased as "mastered techniques" that utilize "every" drop in somethings ability to defend itself. Not a basic skill, but multiple mastered ways of hitting something as it's moving.

There should be some limit to what you can react to, but it's not outside of reason to think that something being pushed/pulled away from someone who is a professional 'moving object hitter' at least has a chance of being hit. Maybe impose disadvantage when the target is being moved more than 15ft from a single event, or if the target is being knocked prone by the force. Like I said, it's left vague enough to go either way as to what you can actually swing at.