If she played with a POG before (and I'm assuming it was an OS), and got tennis elbow with a tweener, then try the recent Radicals.
The Microgel Radical OS is at least an ounce lighter than a POG, but still arm friendly. Its an OS, so lots of margin for error. And its on sale for $89.95.
The Youtek Radical OS may have the same specs, but I tried it and it seems lighter and flexier in the head. More expensive than the Microgel at $127.95, but still a bargain.