While I could post in the main thread about this, I'm instead going to make a fanpost because I deal with this ALL the time at my job and want to really clear it up. I debated whether this was really fanpost-worthy, but here goes.

Colby Rasmus has sat out two games with a stomach condition, probably gastritis (painful stomach lining inflammation), caused by a hiatal hernia. Hernia is the scary part, but this is the main thing I want to clear up. A herniation is any type of protrusion of a structure through the membrane that it should be anatomically confined inside. The scary hernias are sports hernias and herniated discs, both usually resulting from various types of strain and athletic activity (I could explain these further, but I'd rather just get to the point). Other hernias are just annoying, like the hiatal hernia (I think hemorrhoids might be a herniation as well).

At any rate, a hiatal hernia is an extremely common condition in which the top of your stomach begins to protrude through the diaphragm and into the thorax. 

via upload.wikimedia.org

This is almost always asymptomatic, present in many, many adults, and is treated through more fiber intake, and the use of antacids to control the heartburn that it can exacerbate (it promotes reflux because stomach contents can slow or briefly stop their progress above the diaphragm). Large herniations sometimes require surgery, but this is extremely, extremely rare (I've never actually seen one large enough to require surgery).

via download.imaging.consult.com

They are usually an incedental finding on x-ray exams involving the drinking of contrast, and they look exactly like what they are. On the film above the stomach is the big lower blob, the esophagus is the blob that trails off the top of the image, and the hernia is the bit attached to the larger stomach and trapped above the diaphragm that you can see pinching the two. This film is of a bit more serious type of herniation, but you get the idea. You can also see them on normal chest films if there is enough air in the stomach.

In closing:

1. Do not worry. You might have a similar herniation and if you do there is a 90% chance you will never know about it.

2. Colby needs to eat fiber, and the reason eating late at night also causes him problems is that increasing the acid in his stomach and then laying down for several hours also causes reflux, which is made worse by the hernia.

3. Let's drink!