Both teams have admitted that McLaren CEO Zak Brown spoke to Horner several weeks ago about the possibility of McLaren using the new Ford-backed Red Bull Powertrains PU in 2026.
Marshall has recently been working at RBP prior to agreeing to join McLaren as technical director, engineering and design, in January.
That led to suggestions that his move could somehow be linked to a PU deal, but Horner insists that RBP won’t be supplying McLaren.
“No, Rob is not going with an engine,” said Horner when asked about the matter by Autosport. “Of course, a couple of teams have approached us about the power unit.
“Our plan at the moment is to supply two teams because we don't want to overstretch ourselves in the first year, so. And of course, those teams are likely to be the two Red Bull-owned teams.”
Source: Autosport