Political statistician Nate Silver on Monday became the latest strategist to voice their skepticism with President Joe Biden’s ability to run for reelection in 2024.

In a lengthy post on his Substack newsletter, Silver, who founded the data-focused outlet FiveThirtyEight, argued that if Biden cannot run a “normal” reelection campaign, he should “step aside” and yield to another Democratic candidate.

“Democrats would be taking a huge risk by replacing Biden — but they’re also taking a huge risk by nominating him,” Silver wrote in his post. He later adds, “If Biden can’t keep up with the schedule of a typical sitting president running for re-election, or is prone to making errors when he does, voters and the media are going to notice that and Biden will wear his 80+ years like an albatross around his neck.”