"They have had several people that have declined to run, but there's not a lot of really strong Democrats left to challenge Shelley," Tackett said.
After Rockefeller's announcement, several potential Democratic candidates opted against the race.
That includes former Sen. Carte Goodwin, former Gov. Gaston Caperton, Rep. Nick Rahall, state Supreme Court Justice Robin Davis and private attorneys Nick Preservati and Ralph Baxter.
"(Capito is) no amateur to politics, she's very astute. It would take somebody with a lot of money to give her a good race or to beat her," Tackett said.
Capito has more than $2.87 million in hand for her campaign, according to a recent filing with the Federal Election Commission.
Tackett pointed to Capito's time in the House as evidence she could be a tough opponent. Capito was first elected to the House in 2000. In 2008, Capito spoke on the House floor to congratulate Tackett and the state national guard for receiving an award in recognition of excellent performance in managing a military installation.
Secretary of State Natalie Tennant is among the few Democrats to have expressed interest in running for Senate and not to bow out of the race. Tackett said he thinks she's well liked and has "run strong" in state campaigns, but "who knows" how she would fare as a Senate candidate.
West Virginia Democratic Party Chairman Larry Puccio said Friday he thinks Tackett would make an outstanding candidate. But there's still someone who's investigated running, and Puccio expects a campaign announcement in the next 30 days.
He declined to name the person, but said the potential candidate "truly is a West Virginia person that would represent the people of West Virginia."
When asked if Tennant was that candidate, he declined to answer. But he said he gets calls daily from people who want Tennant to enter the race.
Tennant spokesman Jake Glance said Friday Tennant is still considering whether to enter the race.