The president of the Club for Growth encouraged longtime Sen. Dick Lugar (R-Ind.) to retire Tuesday rather than seek another term in 2012, warning that the group could get involved in the effort to oust Lugar in a primary.

In an interview on ABC's "Top Line" webcast, Club for Growth President Chris Chocola said while no decisions have been made as to whether the club will officially weigh in on the race between Lugar and Indiana State Treasurer Richard Mourdock (R), "we do have some concerns about Sen. Lugar and his service."

"We think it would probably be best if he would retire at this point," Chocola said of Lugar, who has vowed to beat back a primary challenge and win another term in 2012. "We haven't made any decisions at this point, but we are looking at it very closely, and it's one of the races very high on our radar."

Chocola said the group is also waiting to see whether strong primary challenges to GOP Sens. Olympia Snowe (Maine) and Orrin Hatch (Utah) develop ahead of next year.  

Backing from the Club for Growth could translate into a significant fundraising boon for Mourdock if the group endorsed in the primary and used its network to help raise money. 

Lugar is sitting on a $3 million war chest ahead of 2012.

In Arizona, the Club has already raised more than $350,000 for Republican Rep. Jeff Flake's 2012 Senate bid. An early favorite of the Club, Flake was endorsed by the group the same day he declared his intention to run for the upper chamber.

Flake brought in more than $1 million during the first quarter of the year — nearly 35 percent of those contributions were earmarked through the Club for Growth.  

Chocola also continued his group's battle with real estate mogul Donald Trump on Tuesday, telling "Top Line" that while Trump is a "great showman," he's no fiscal conservative. 

"We are not fearful of his candidacy at all, but he is not conservative, he is not pro-growth and he is not a good choice for economic conservatives," Chocola said of Trump.