Despite his ever-expanding portfolio in the House, Rep. Chris Van Hollen (D-Md.) on Wednesday would not rule out the possibility of running for Senate in 2010, if four-term Sen. Barbara Mikulski (D-Md.) decides to retire.

Van Hollen has agreed to serve a second term as chairman of the Democratic Congressional Campaign Committee and has also been appointed Assistant to the Speaker — a post in which he is expected to be the chief House liaison to the administration of President-elect Barack Obama.

But Van Hollen told reporters during a news conference Wednesday morning that if there is a Senate opening in the Free State in 2010, “it’s something I would have to take a look at.”

He quickly added, however, “there’s no indication there’s going to be a vacancy.”

By all accounts, Mikulski is planning to seek a fifth term. But she will be 74 in 2010, and if she chooses to retire, several ambitious Maryland politicians are certain to take a long look at running for her seat. When then-Sen. Paul Sarbanes (D-Md.) announced his intention to retire at the end of 2006, Van Hollen was one of several House Members from Maryland who pondered running, though he eventually decided to forgo the race. Then-Rep. Benjamin Cardin (D-Md.) wound up winning Sarbanes’ seat.

While Van Hollen refused to rule out a 2010 Senate run, his House workload could make it difficult for him to pivot into a statewide race. He would presumably have to give up the DCCC job to campaign for Senate and might also have to relinquish the Assistant to the Speaker position.

Van Hollen said he is happy to have two roles that will enable him to mesh policy and politics. He said that after picking up a minimum of 54 seats in the past two election cycles — two races still haven’t been called, and a competitive race is taking place in Louisiana’s 4th district next month — House Democrats are prepared to play defense in 2010.

“Just being realistic, we’re going to fight hard to hold the line,” Van Hollen said. “Our major focus will be helping in the toughest districts. That doesn’t mean we aren’t going to look for opportunities” for places to play offense.

Sources said the DCCC’s 2008 recruiting team, which helped find candidates for competitive races in the cycle that just passed, is expected to meet Thursday morning to discuss races where Democrats lost narrowly and where a vigorous push by the committee in the 2010 cycle could make a difference.