After spending much of the last week out of public view while President Biden was besieged by Democratic doubts, former President Donald J. Trump will return to the campaign trail on Tuesday evening with a rally at his luxury golf resort in Doral, Fla.

Mr. Trump’s rally, at the Trump National Doral Golf Club, comes as the deadline for him to select a running mate is fast approaching. His pick will be formally nominated during the Republican National Convention, which starts on Monday, and advisers have said Mr. Trump will likely make his selection known before the convention begins.

Tuesday’s rally will be watched closely for any hint at whom Mr. Trump might pick, and Senator Marco Rubio of Florida, one of the top contenders, is expected to speak before Mr. Trump takes the stage.

But though Mr. Trump typically enjoys dominating headlines and has for months relished the spotlight that the speculation over his running mate has brought, he has largely been content to stay out of the spotlight in the last two weeks, as President Biden has grappled with the fallout of his stumbles during last month’s presidential debate.

As Democratic panic over Mr. Biden’s fitness spiraled, prompting questions of whether he should remain on the ticket in November, Mr. Trump for days largely refrained for commenting, a strategy that advisers said reflected his desire for Mr. Biden to remain his opponent in the fall. He did not conduct any interviews or hold any public events.

But Mr. Trump entered the conversation late last week with social media posts in which he mocked Mr. Biden. And during an interview on Fox News on Monday night, he told Sean Hannity that he thought Mr. Biden “may very well stay in” the race, something Mr. Biden has said firmly that he will do.

Mr. Trump also acknowledged that his campaign had been preparing for months to tackle Mr. Biden. “Well, we have prepared for him,” he said when asked if he thought Mr. Biden should step aside. “But I don’t think it’s going to matter.”