"I'll make that decision in time," he said, and offered no timeline for the decision when pressed.

Democratic sources say the 75-year-old senator will have to decide within the next 4-6 months if he'll retire to give prospective Democratic candidates enough time to organize and raise funds to mount a credible challenge in the increasingly red state. But he's given little indication of his thinking, and sources in the state say they have no reason to believe he'll step down.

Rep. Shelley Moore CapitoShelley Wellons Moore CapitoPa. health secretary: 'Sustainable funding' needed to attack opioid crisis Senate panel unanimously approves water infrastructure bill The Hill's Morning Report — Sponsored by PhRMA — How long can a Trump-DOJ accord survive? MORE (R-W.V.) threw her hat in the ring for the Republican nomination on Monday. Republicans believe she's one of the strongest possible challengers in the state. She's expected to consolidate establishment support behind her easily, though she could face a challenge from conservative groups unhappy with her spending record.

But Rockefeller said he was "not at all" concerned about her bid.