WASHINGTON — Ohio Republican Sen. Rob Portman, who lags in early polls for his re-election bid, nonetheless has more than $10 million on hand for a Senate bid that’s more than a year away.

Portman’s campaign announced on Monday that he raised more than $2.9 million during the second quarter of 2015 — up from the $2.75 million that he raised during the first quarter of this year.

“That’s a lot of money,” said Jennifer Duffy, a Senate expert with the Cook Political Report.

By contrast, Portman’s Democratic opponents, former Ohio Gov. Ted Strickland and Cincinnati City Councilman P.G. Sittenfeld, raised $670,000 and $750,000, respectively, during the first quarter. Neither has released a fundraising report for the second quarter.

Portman has lagged Strickland in the two most recent Quinnipiac University polls. But his campaign has launched repeated digital ad buys and worked on building a strong ground game, making more than 100,000 voter contacts through both door-to-door campaigning and phone calls.

In the most recent Quinnipiac Poll, released on June 22, Strickland led Portman 46 to 40 percent. But Portman topped Sittenfeld 49 to 24 percent.

Sittenfeld and Strickland must face off in a Democratic primary next spring with the winner likely facing Portman in November 2016.

Portman’s campaign released the figures on Monday morning for the period between April 1 and June 30. The reports are due to the Federal Election Commission by July 15. Once those are filed, it will be made public who donated how much to the campaigns.