A small shift in research firm IDC’s 2013 tablet projections speaks volumes about the mobile market.

IDC has lowered its tablet shipment forecast to 227.4 million units for the year, down from its previous projection of 229.3 million, it announced this morning.

Like many, IDC apparently also didn’t predict Apple’s lower-than expected iPad sales for the last quarter, which came in around 2 million units short of analyst estimates (at 14.6 million). As much as it points to growing computer trends, IDC’s forecast adjustment seems centered on the iPad.

Overall, tablet shipments this year will still be 57.7 percent higher than 2012’s. IDC also still expects to see tablet shipments at 407 million units by 2017.

Perhaps more interesting than the forecast adjustment, IDC also notes that growth in developed areas like the U.S., Western Europe, and Japan, will slow more quickly than expected. In particular, the firm points to the growing influence of smartphones with screens larger than five inches, the eventual impact of wearable computing, and simple market saturation. Given that these are the markets that fueled the initial surge in tablet demand, it makes sense for things to slow down as they get saturated and new technology appears.

IDC now expects mature markets will account for only 49 percent of tablet shipments by 2017, down from 60.8 percent last year. Conversely, emerging markets like Asia (not including Japan), Latin America, and the Middle East will make up half of tablet shipments by 2017.

“A lower than anticipated second quarter, hampered by a lack of major product announcements, means the second half of the year now becomes even more critical for a tablet market that has traditionally seen its highest shipment volume occur during the holiday season,” said Tom Mainelli, IDC’s  research director of tablets, in a statement today. “We expect average selling prices to continue to compress as more mainstream vendors utilize low-cost components to better compete with the whitebox tablet vendors that continue to enjoy widespread traction in the market despite typically offering lower-quality products and poorer customer experiences.”