After last week’s debate in Boulder, Colo., Rubio tried to initiate a phone call with the Wisconsin governor, who dropped out of the race for the Republican nomination in September. A source close to Walker, who requested anonymity to discuss the outreach, said the two connected by phone on Friday.

That conversation, which lasted between 15 and 20 minutes, began with friendly banter. The Florida senator asked Walker what he’d been up to since he departed the primary. Toward the end of the conversation, the source said, Rubio made a “hard ask” for Walker’s support.

Walker, though, is not planning on making an immediate endorsement of anyone in the GOP field. During the conversation, the Wisconsin governor told Rubio that he had not made a decision on whom he was backing and that he would not announce his support for a candidate until after the start of 2016.