The 20-year-old confirmed this via his Instagram page after admitting during a conversation with a fan that he had been training with the Championship side.
Ward returned to Tottenham's pre-season camp last week and posted a picture of himself in his Spurs gear over the weekend.
This week he has seemingly been with Rotherham, and was quizzed by a supporter whether this was the case, responding, admitting, asking the fan how he knew it was the case.
- mightymillers1983 Was with the Rotherham today wasn't you grant?
- grantward123@mightymillers1983 yh how do u know ?
- mightymillers1983 Just from lads that go watch the players train mate. Hope you enjoyed it
The exchange was also reported by the Coventry Telegraph, which has an interest in Ward due to the time he spent on loan with the Football League side last season.
Their report states that Ward is expected to be making a season long loan to the Championship side, rather than a permanent switch.
Ward can play in central midfield or on the wing, and previously had a spell on loan for MLS side Chicago Fire. He has made 15 appearances for Tottenham's under-21 side, scoring three goals, and featured in the first team's post-season tour of Australia and Malaysia just weeks ago.