The head of a group backed by Senate Majority Leader Mitch McConnell was skeptical Friday about how primary challengers to Sens. Jeff Flake and Dean Heller would fare in a general election.

Steven Law, the president of the Senate Leadership Fund, said that the challengers to Flake, R-Ariz., and Heller, R-Nev., have "real baggage." Danny Tarkanian, a perennial candidate, announced plans to potentially take on Heller earlier this week. Kelli Ward is challenging Flake for his seat a year after handily losing a primary fight to Sen. John McCain, R-Ariz.

"First of all, I don't think either one of them are going to win," Law said during an interview with C-SPAN's "Newsmakers."

"In Nevada, we'd have real concerns about putting Danny Tarkanian up against the very same Democrat who gave him his fifth strikeout in a row in the last congressional election," Law said, referring to Rep. Jackie Rosen, D-Nev., who beat Tarkanian by just over a point in November. "I would be very concerned about his competitiveness in a statewide race for that reason."

"I'm not even sure [Kelli Ward] will end up being the primary opponent of choice against Flake by those who are concerned about Sen. Flake's opposition to Trump," he said. "I think both of them have real baggage. It would be very hard for either of them to be competitive in a primary, let alone in a general."

Ward is trying to win support from Trump backers against Flake, although Jeff DeWit, the Arizona state treasurer and a prominent Trump supporter, might jump into the race. However, Robert Mercer, a top donor to Trump, is donating $300,000 to a super PAC backing Ward.

Law also expressed confidence in Heller's ability to win the 2018 general election.

"I actually feel like we're going to end up by September of next year, feeling like Dean Heller's in pretty good shape," Law said. "I really do."

The Senate Leadership Fund is a group backed by McConnell, R-Ky., designed to protect the GOP's majority in the upper chamber.