NEW YORK (TheStreet) -- Yahoo! (YHOO) confirmed that it's changing some key slots on its management team, but these moves are likely being made from a position of weakness rather than strength.

In confirming that Yahoo! had undergone another reorganization, CEO Marissa Mayer promised that this reorg would spawn rapid growth for the company. Given that the company reports first-quarter earnings next week, the timing of last week's announcement suggests those earnings will be very disappointing.

Last October -- a month after Starboard Value LP sent a letter to Mayer complaining about the pace of the turnaround -- Mayer held an earnings call in which she trumpeted the growth of the core business. She began pointing to mobile, video and Tumblr as the future of the core business. She said she would start to report the financial figures of these businesses as they were now material to Yahoo!, and promised that Tumblr would do $100 million in revenues in 2015.

It all sounded great, but now, less than six months after that earnings call, Mayer is changing the leadership of Tumblr (at least in the sense that the Tumblr group will no longer report directly to her), mobile and video. You don't do that unless there are problems in those areas.

Former Flurry CEO Simon Khalaf is getting a promotion to essentially take over Mike Kerns' old role as SVP of consumer facing products, while Tumblr CEO David Karp will now report to Khalaf. Adam Cahan will no longer head "mobile" for Yahoo!, but is instead being moved over to "video." That would appear to be a demotion of sorts. Jeff Bonforte, who used to head mail and communications for Yahoo!, will now oversee mobile.

What all of these moves suggest is that the turnaround of Yahoo!'s core business has now stalled.

Mayer came into Yahoo! almost three years ago under-promising, and saying that it would take at least five years to turn the company around. Since then, nothing much has really happened to the business except continued contraction.

The Information's Amir Efrati tweeted last week that you shouldn't " hold your breath" to see Tumblr do $100 million in revenue this year. Tumblr's former head of revenue left the company to join BuzzFeed a couple of months ago in a move that perhaps suggested problems -- or at least that the BuzzFeed job was more attractive.

Can you criticize the management abilities of the new Yahoo! management team compared to the old one?

It's really difficult to from the outside. I think it's totally fair to point out that these new people in charge -- Khalaf, Cahan, and Bonforte -- all have little "big company management" experience, unless you want to count Bonforte's previous stint at Yahoo!. All came into Yahoo! from acqui-hires.

If Yahoo! was killing it in mobile, why switch out Cahan for Bonforte? If Yahoo! Screen was taking the world by storm in video, why move Cahan over? I have no idea whether Khalaf is up to the job of handling consumer-facing products. I did think it was odd at the recent Yahoo! developer conference that he got up and described how central messaging apps (like Kik, which has recently hired Qatalyst, and would be a natural acquisition candidate for Yahoo!) are to the mobile world and then had to be corrected onstage by Mayer that they don't have a messaging product.

The bottom line here is that you should expect things at Yahoo!'s core business to get worse before they get better with these recent management changes.

Ironically though, that won't necessarily be bad for Yahoo! stock. The core business already has a steep discount attached to it if you add up Yahoo!'s cash, the after-tax value of its stake in Yahoo! Japan, and its soon-to-be-spun-out tax-free stake in Alibaba  (BABA). The core business is effectively valued at zero or significantly less than zero.

Even if things get worse, how much more of a discount can Yahoo!'s core business receive?

This article is commentary by an independent contributor. At the time of publication, the author held long positions in Yahoo!, Kik and Alibaba<./I>