At the moment, you cannot buy an AT&T (T) Android phone with an OS that is under a year old.   Think about that for a second.  As far as 2010 Android OS’s, AT&T wasn’t interested.  Android 2.1 was released in January of last year.  Android 2.2 came in May and Android 2.3 was released last month.

At the top of AT&T’s current lineup, Dell’s (DELL) Streak, Samsung’s Captivate, HTC’s Aria and Sony’s (SNE) Xperia X10 are all running year old OSes.  That’s a death penalty in the smartphone business as you can see in the graph provided by the NYTimes at right.

(Samsung’s Galaxy Tab, which is carried on all four big networks runs Android 2.2)

I noted this disparity in May, so it isn’t news to anyone at AT&T.

Now, all of that is hopefully about to change.   AT&T CEO Randall Stephenson told analysts today…

“We have not been very aggressive with the Android portion [of the wireless device market],” he said. “We will be a heavy participant in the Android market this year.”

If CES is any indicator, he might be on to something.

BGR points out that AT&T is finally getting on board with Android at just the time they are losing Apple (AAPL) iPhone exclusivity.

AT&T will look to regain its perceived position as the top smartphone provider in the U.S. where variety and power are concerned. Up to this point, AT&T has been very slow in adopting Android, likely as part of its efforts to keep Apple happy. It did launch a few Android smartphones of course, but none that could compete with the high-end devices being offered by competitors.

The timing is surely just a coincidence.  In any case, AT&T are going from worst Android carrier to just about the best in the same month they lose iPhone exclusivity.

AT&T now has the 4.5 inch AMOLED “thinnest” Samsung Infuse, the Motorola (MMI) Atrix, which doubles as a laptop,  HTC Inspire4G — all of which are world class Android phones.  AT&T will even carry Motorola’s XOOM tablet, amongst others, promised for 2011.

There’s even some credible evidence that AT&T might even carry Google’s (GOOG) own Nexus S phone.  For some strange reason (see above), AT&T refused to subsidize the Nexus One last year even though a special version was built for its network.  Now that Cupertino’s chains are perhaps off, AT&T can rethink possible™.

Update: Leaked documents show that AT&T expects to be the Android Leader in 2011.