Gretchen Ertl/AP Photo

Former Massachusetts Republican senator Scott Brown will not seek out his old job in the June 25 special election to fill John Kerry's seat, sources tell ABC News.

Brown, 53, was considered the strong favorite to win his party's nomination if he had wanted to run, and polling indicated that he would have been well-positioned to win the race. However, over the past several weeks several reports indicated that Brown was leaning against declaring his candidacy and was instead eyeing the governor's mansion as his next political target.

In 2014, the current governor, Deval Patrick, will be term-limited, so the gubernatorial race will be open. Historically, Republicans in the state has fared relatively well when seeking the governorship. Republicans Mitt Romney and William Weld are perhaps two of the state's best known governors.

With Brown opting out of the race, the chances of a Republican pick-up this summer are lessened. Weld, as well as former lieutenant governor Kerry Healey (who served with Romney) are seen as a possible candidates who could mount a strong campaign against the current Democratic candidates, Reps. Ed Markey and Stephen Lynch, but beyond those two, there are not too many well-known, established Republicans in Massachusetts.