New York Republican gubernatorial candidate Rob Astorino is not taking the lack of an endorsement from Gov. Christie well and thinks the reason is related to Bridgegate.

Gov. Chris Christie, right, greets Connecticut Republican gubernatorial candidate Tom Foley. (AP Photo/Jessica Hill)

During a campaign stop in Connecticut on Monday for GOP challenger Tom Foley, Christie said he "doesn't "invest in lost causes" and campaigns only for candidate "where I can make a difference to help somebody win." Democrat incumbent Andrew Cuomo holds a wide lead over Astorino in the polls.

Astorino believes that Cuomo is holding something related to Bridgegate over Christie's head and has traded an endorsement for silence.

“Whatever Gov. Christie knew or didn’t know is probably the same for Gov. Cuomo," Astorino told CBS New York. "And if there’s anything being held back that Gov. Cuomo knows and if he’s holding that over Gov. Christie’s head, I don’t know."

The Republican also thinks that Christie has forgotten his that he too was once an underdog and should step down as head of the Republican Governor's Association. "If Gov. Christie is unable to help a Republican candidate for governor, maybe he should consider stepping down as chairman of the RGA, Astorino told the New York Observer. “That’s his job, to go around the country … I would welcome the governor to come here to New York to assist us.”

It's not the first time Astorino and Christie have exchanged words. Last December the New York Post reported Christie had promised Astorino an endorsement even before the New York State primary was held, a decision that did not sit well with Cuomo. Christie admitted talking to Astorino at a meeting of the Republican Governor's Association but only about their respective families.

Astorino told the Observer that he and Christie have a "good relationship" but it's not his job to decide his chances of defeating Cuomo.