This straddler is a good player and usually raises about 50% of the time if no one else has raised pre.

How do I play against him from say MP2 (assume UTG+1 and MP1 have folded)

Should I look to trap limp/re-raise almost all my strong hands?

Or should I have a range for open raising, looking to get HU IP vs the Straddler, and denying the players behind me the chance to see a flop cheaply on the occasions that the straddler does not raise pre?

First move directly to his right.
Then you’ll be able to “close” the action on him when he chooses to raise his straddle.

Only call pre if you’re comfortable knowing he might three bet.

And occasionally you can limp trap him when he makes it $15 gets four callers and you make it $100 to steal (or for value)

Playing mid position against him is horrible because any money you put in can be raised (by him first or other players looking to steal light)

Either be multiple positions to his left or his direct right.

Direct right and make sure your sizing is a little larger since if he is raising 50% of the time it’s safe to say his terrible % of straddle raises shows he is likely to flat a lot of his hands and he probably bases this off of how much he is going to have to call, or he truly does not care and will call any sizing (good for you in those limp 3B spots).

I have trouble seeing how both parts of this sentence can be true. (I have serious trouble with the clause "The straddler is a good player" on its own, if the straddle is an UTG straddle.)

If this person is winning, it is because their aggression forces the other players outside of their comfort zones.

The obvious adjustment is to get comfortable with aggressive poker.

What, and have your equity in the big blind stolen by this character and passed along to the people acting after them? To say nothing about being out of position relative to an aggressive loose cannon eight hands out of nine.

Agree with the above player that someone else straddling utg & raising a lot can't really be a good player.

Move to his direct left & lrr your entire (very tight) range would be a good option. I'm not messing around much from spots like mp2.

His direct right can be good option to lrr as well, after he raises & possibly pulls a few other people into the pot. The downsides of being oop vs this guy in every other position outweighs the potential benefits tho imo.

Actually the right spot to be with a straddler is three spots to their right, so that when they are straddling we have the button.

A straddle is a bad play IMO, and most straddlers are bad players, but good players do straddle sometimes.

Are you saying he 3 bets a lot or that he raises vs some limpers

If say two or three people just call the $5 straddle then he will raise ($20 more) about 50% of the time

You have some options

1. Exploit him pre/post
2. Just fold
3. Don't limp/only limp if you will call a decent raise

If I'm OOP I'd limp 3 bet with a wider value range. If I'm in position, 3 bet with a wider value range. The exact frequency and hands would depend on how often he flats and his post flop tendencies.

I love to limp/rr these players. Just be sure you have the goods AK QQ+ because other Vs might have the same idea. When you execute this, choose sizing that will take down the pot pre. If V raises straddle to $25, four callers, make it $150.

I'll agree with you when it comes to a standard UTG straddle (which I assume is what's being discussed here) but I don't think all straddles in general are bad. BTN straddles can be cash cows against passive lineups.

I would be L/RRing nearly my entire range, although his playstyle wont last long if you do. You should be limping in something like AT+, KQ, and mid to high PPs and reraising with all of them.

Then raise pre yourself.
L/rr pre helps us win a mediumsized pot around 50% of the time, whilst going to a multiway flop in an inflated pot the other 50% of the time.
Meanwhile, thanks to the straddle when we raise we get extra value with our strong hands and "extra" fold equity with our weak hands, due to the nominal value of our bets being 2x the size.

Just be aware that the straddle effectively halves the stacks, but otherwise our gameplan shouldn't really change.

+1.

Deliberately sitting to his direct right sounds like a terrible plan. We'd have to give up our BB like 90% of the time.

Typically, BTN straddles are terrible for the game/action. UTG straddles are good for the game/action, which is why good players should sometimes straddle also. Don't be a nit and help get the game out of the muck, ffs.

if that is true he really can´t be good.
as another poster said, get comfortable with aggressive poker.

an overly aggressive player is a bad player though, and you want to get involved in as many hands as possible with a bad player, even if his leak is one that makes you uncomfortable bc it might lead to a higher variance than you´d like.

You want to play hands with him, so the answer is NOT to nit up.

I’ve played with this player quite a lot and seen him to be an excellent winning/creative player. Good players sometimes straddle. He is not overly aggressive in any other spots on later streets, straddling is really his only overly aggressive move. Yes he is quite aggressive on later streets but always in a well thought out way which makes him tough to play. There are enough good players around who fit this profile to make it worthwhile thinking about how to play them IMO.

I’m more likely to be loosening up than nitting up tbh (but I’m open to advice if people advise for example limping with a tight range with the plan of re-raising, which seems one possible good strategy)

Position is interesting.

I like the idea of being on the right of this player for the spots where I can trap-limp- reraise when he straddles and when his raise then gets a couple of other callers.

I generally like to be on the right of frequent raisers/loose cannons (but this guy isn’t really a loose cannon, he’s just creatively aggressive and tough to play against). Being on his right would mainly be designed for the particular one-hand-out-of-nine (his straddle). I’m not too bothered about often surrendering my BB, because there is massive benefit when I do trap-limp-reraise when other players call his raise and I’m closing the action.

But usually I like to be on the left of good/tough players, which is good for 8-out-of-9 hands here.

So it’s quite balanced IMO regarding what position I want against this particular guy.