Roll Call rated seven seats as toss-ups, all the candidates -- incumbents and challengers alike -- have healthy bank accounts, the publication reported Thursday.
Democrats have 23 Senate seats to defend compared to the Republicans' 10. The GOP must add four seats to pick up a majority.
Democratic strategist Jeff Pollock of Global Strategy Group said, "It's no secret our side has more seats to defend, and the [Democratic Senatorial Campaign Committee] has made sure our candidates have their campaigns in order."
Pollock said Democrats expanded the playing field by good recruiting in Arizona, where Republican Sen. Jon Kyl is retiring, and Massachusetts, where Harvard University professor Elizabeth Warren is challenging GOP incumbent Scott Brown.
"So we have reason to be optimistic about how things will turn out when the American people choose which party they want leading the country," Pollock told Roll Call.
"As much as I would like to believe that 2012 will be a wave election for Republicans, it is unlikely to be so at the presidential level," Scott Bensing, a former executive director at the National Republican Senatorial Committee, said. "It will be close, meaning that high-quality Senate candidates and well-run campaigns will win the day."
Roll Call lists as toss-ups open Democratic seats in New Mexico, Virginia and Wisconsin; the seats of Democratic Sens. Claire McCaskill in Missouri and Jon Tester of Montana, and the seats of Republicans Sens. Brown and Dean Heller of Nevada.
Financial reports filed with the Federal Election Commission indicated Heller collected $1.1 million.
Brown raised $3.3 million during the last quarter to try to retain his Massachusetts seat.
McCaskill, Tester and former Virginia Gov. Tim Kaine led Republican opponents, with all having at least $1.3 million in the cash advantage, Roll Call said of its review of the FEC documents. In Wisconsin, Democratic Rep. Tammy Baldwin, raised $1.2 million last quarter and likely will face either former Gov. Tommy Thompson or former Rep. Mark Neumann in the general election.