With Yahoo!'s (NASDAQ:YHOO) shares smooching five-year lows, at least one investor wants Microsoft (NASDAQ:MSFT) back.

Mithras Capital partner Mark Nelson is calling out to both companies, hoping to play Cupid at a $22 price point. At that price, Nelson argues, Microsoft can essentially buy Yahoo!'s search business for $10.3 billion, after cashing out of Yahoo!'s Asian stakes and non-search businesses (and extracting $3 billion in cost savings and $2.8 billion in tax benefits).

It's a fair argument, but why should Microsoft pay that much? When it offered $31 a share for Yahoo! back in January, Yahoo!'s Asian assets were worth roughly $10 a share, Yahoo! was more relevant in search than it is today, and the market hadn't crashed.

Google (NASDAQ:GOOG) closed at $564.30 the day that Microsoft found itself on bended knee for Yahoo!. Google trades 43% lower than that today, and it's been gaining market share at Yahoo!'s expense. Is Microsoft stupid enough to simply mark down its original offer by just 29%, when Yahoo! investors would probably gladly hand the company over in the mid-teens?

And are we so sure that Microsoft would want to bail on Yahoo!'s stakes in China's Alibaba, Yahoo! Japan, and South Korea's Gmarket (NASDAQ:GMKT)? If Microsoft is serious about taking on Google, it's going to have to do so with its passport clenched in its fist.

I do think a deal with Microsoft is possible. It certainly makes more sense than its subtraction by multiplication potential pairing with Time Warner's (NYSE:TWX) AOL. However, the terms of a deal won't be called out from the Yahoo! camp, and any premium will have to be realistic.

Yahoo! blew its shot at a sweet exit strategy. Now it can only hope for a bittersweet way out.

Read more about Yahoo!'s real worth:

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Longtime Fool contributor Rick Munarriz spends plenty of time on Yahoo!'s sites, but he does not own shares in any of the stocks in this story. He is also part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early. The Fool has a disclosure policy.