Machado played shortstop in the minors, but has been at third base since making his debut with Baltimore in 2012. He won a Gold Glove at third in 2013.
Manager Buck Showalter made the switch in an effort to shake up a club that has lost 10 of 11 games.
Showalter says: ''Sometimes you're in need of a little different look.''
J.J. Hardy has been a mainstay at shortstop for Baltimore, but he is on the disabled list with a groin strain.
It's uncertain if Machado will stay at shortstop until Hardy returns.
Showalter says: ''We're trying to win and this gives us the best chance tonight.''