Zendikar Rising (see "’Zendikar Rising’ Product Line Revealed") will still be headed to North American retailers in two waves. However, the first wave is now facing delays, and certain locations might not receive their full allotment of Draft and Set Boosters for release day. The second wave is subsequently also delayed, and certain locations will experience limited product availability when the second wave hits. Luckily, product for prerelease weekend will not be affected by these delays.
These further delays do not bode well for the hobby market supply of Zendikar Rising. With one distributor cut from WotC's roster (see "WotC Says ACD Distribution ‘No Longer an Option’"), retailers were already sent scrambling to arrange alternatives for September releases. A shortage of product within the release waves could create another scramble, and seriously impact the timeline on filling customer preorders of sealed product and singles.