Those 2X6's (not 2X4's) could be providing some support for the stairs. Also, the stair construction looks a little sketchy to me in the first place: 1) there is no central stringer for better structural support, 2) it's hard to tell what the stair construction is because of that outer casing on the stringer that appears to be scabbed together from four short pieces, and 3) I can't tell how the risers and treads are actually mounted to the stingers. I'm not saying your stairs will collapse if you remove those vertical pieces, but I suspect they could be shakier afterwards. If you want to be sure, get a structural engineer to advise. It's just too hard to tell from the photo how well-constructed the stairs are and whether they are adequate to allow removal of those verticals.

Hi, I am trying to open up the space underneath basement stairs. Can I remove the 2x4’s in the red circle?

If it’s your house, you sure can! Just remember, though, that any advice you get on here is worth what you’re paying for it.

Maybe these pictures would help understanding... I am pretty sure they are 2x4’s. There’s no center stringer and I guess because the stairs are only 32” wide?

They appear to be built like the stairs to the upper level of my shop. I can guarantee you that the steps in the shop would collapse in a heap on the floor if those supports were moved. I suspect the same would happen to yours. For sure, they would be pretty darn wobbly and could be dangerous.

Sean-

On second look, they are 2X4s...and my comments are still the same. :-)

An experienced carpenter should be able to help you. It would be a pretty easy job to make sure all the connections are adequate, add what might be needed, then remove those studs. An engineer? Collapse in a heap? As I said above, hire someone who knows....

I wouldn't do it. But then, I'm not a structural engineer.

Actually, that's why I wouldn't do it. I'd assume that the architect who designed the stairs knew a lot more than I did about what it took to hold them up.

My guess is the frame was added sometime after house was built but I hear you, I should not take any risk when it comes to structural issue.

You said what part of stairs needs to be rebuilt???