The 78th Masters will begin with honorary starters Arnold Palmer, Jack Nicklaus and Gary Player teeing off at 7:40 a.m., and will conclude with the group of Harris English, Lee Westwood and Russell Henley at 1:59 p.m.
Garcia finished third at the Shell Houston Open last week, while McIlroy shot a final-round 65 and tied for seventh.
Scott, Stenson and Day all have opportunities to supplant Tiger Woods as the No. 1 player in the World Golf Ranking. Woods, a 14-time major winner, is not playing the Masters after having a microdiscectomy procedure on his back last week.
Competitors will play in the same groups on Friday with their tee times altered.
The field size will be cut to the top 50 and ties and anyone within 10 strokes of the lead through 36 holes.
The complete list of tee times can be found here.
ESPN will televise the first and second rounds of the Masters live beginning at 3 p.m.