A recent poll from Suffolk University indicated Obama's popularity in the state had declined since May, and that Massachusetts voters were both aware of the series of scandals and skeptical of Obama's response to them.
Markey is favored to win in the deep-blue state and has led Gomez in every poll of the race, but the Republican has kept his lead to single-digits.
The tigh polls have prompted concern from Democrats worried the party could suffer the same upset that sent Republican Scott Brown to the Senate in the 2010 special election.
Carney brushed off the suggestion that Democrats are still stinging from Brown's victory over Democrat Martha Coakley. He said president is visiting Massachusetts simply because he wants to support Markey's campaign.
"The president supports Ed Markey's candidacy, as you would expect, and believes he'll make an excellent senator. And that's why he is traveling here to have a rally in support of Congressman Markey's campaign," he said.