PO to Scrum Master?

Why has your new company chosen to use Scrum, and is there commitment from those in leadership positions to be successful with it?

If your new company doesn't even have a Product Owner, do they consider that they're using Scrum?

I also don’t want to step on anyone’s toes.

It's very hard (perhaps impossible) to be a successful Scrum Master without stepping on toes. You will need to make things transparent, particularly when there are issues that people are not addressing. In doing so, you might threaten existing power structures within the organization.

Who is currently accountable for maximizing the value delivered by the team? Who is prioritizing the Product Backlog? In pointing out that a Product Owner is required for Scrum, you might tread on this person's (or these people's) toes.

That's a tough choice. Though I've seen Product Owners temporarily step into the role of a Scrum Master, I haven't met one who switched permanently. On the other hand, I have seen Product Owners move into an Agile Coach role. 

Since you've been on a Scrum Team for a few years, know that you are there to support the Product Owner. You can coach them but don't offer to train or mentor (based on your experience) unless explicitly asked to do so.

I’ve been a PO for about 3 years and next month will be starting a job at a new company as Scrum Master. I’ve never done this before, and am a bit wary of their expectations...they don’t currently have a PO 

Scrum is not a pick and choose framework. Are you sure you can fulfill the Scrum Master role at a company where product ownership is lacking?

What made you choose to switch to the SM role?

In every industry, in every company, in every position there will be challenges and pitfalls. You obviously are switching into this company because it offers something worth while. 

When faced with a pothole of sorts, put your best foot forward, don't make it personal, be a consummate professional and always, always remember this:

Scrum Teams create functional software. That's it. That's your job. Facilitate great software development. 

If the client is happy, the team is happy and they hit their Sprint Goal, you've done a great job as a Scrum Master. 

Good luck!

I have known someone that moved from a Product Ownerrole to a Scrum Master role and they were successful. But it took effort on their part to focus on doing Scrum Master and not Product Owner.  In your case where there is no Product Owner you are going to feel even greater pull to fill the empty role. You will have to constantly remind yourself that you are there to focus on the team aspect and their appreciation of Scrum. You have to constantly remind yourself that you have no real interest in the work that they are doing but are interested in the way they work together. 

You said you are worried about their expectations.  Did you not discuss this with them during the interview?  This is always the question I ask everyone that interviews me ... "What are your expectations for the person that will be filling this position"? 

Good luck because this could prove to be difficult.