On Friday, a photo with the words "Scott Walker Is Running For President" was tweeted from Walker's account.
A Twitter spokesman said Friday night that the tweet wasn't the Walker campaign's fault:
"We're looking into today's issue, and we've determined the Walker team was not at fault," the spokesman said in a statement.
Twitter did not provide further information on what exactly happened.
On Monday, Walker is expected to announce his candidacy, which will be the culmination of a lot of early pre-official campaigning for most of the year.
Since Iowa Freedom Summit this winter, he has aggressively campaigned in early presidential primary states this year and is considered a top Republican contender for the nomination.
The Wisconsin governor is best known for his battles with public unions. After he passed a budget that required public workers to contribute more money to their pension plans and limited collective bargaining in the public sector, unions protested for weeks, and ultimately helped force a recall election in 2013, which Walker won decisively. Because of the recall, the Republican has won three statewide elections in a blue state.
Early on, Walker has focused on his conservative record and pitched himself as a slightly more populist alternative to many of the other prospective candidates.