Could be basic speculation but here's this from AutoRacingSport.com:
Reports are surfacing that NASCAR Toyota Red Bull Nextel Cup driver A.J. Allmendinger is trying to get out of his NASCAR contract with Toyota and move to the Indy Racing League in 2008.This goes along with a Yahoo! Sports report that also said Allmendinger is longing to return to open-wheel, but in that previous story it was mentioned that AJ was already under contract with Ganassi. Well, which is it guys?
Allmendinger has had a difficult rookie campaign in Nextel Cup with the first year Toyota Red Bull team and there may be as many as three top tier rides up for grabs in the open-wheel series: Ganassi’s IRL operation (if current driver Dan Wheldon leaves), Team Penske (he would replace the ‘almost sure to be departing’ Sam Hornish) or Andretti Green Racing (in place of Dario Franchitti).
Above all, remember this folks: Mario Andretti loves Allmendinger.