Yes it can easily mean too much water. It can also indicate poorly draining soil which only compounds the water issues. And a lack of nutrients can also contribute to the problems. But too much water is the first issue to address.

Dave

Since the plants have only been in the ground for a couple weeks would it be ok to dig them back up? I can make a minature raised bed and replant them.

If they've only been in the ground for several weeks, it's very likely that enough roots haven't yet developed to support the plant.

How do you water -- hand? drip? sprinkler? or?
How often?
How long?
Where, specifically, is the water applied?
(During the several weeks after planting, it must be applied to the existing root area. and that assumes that the garden bed was moist when the plants where put in.)

Jean -

It is planted at the edge of my garden so it gets watered by the sprinkler. The temps have been very high for this time of year (80's & 90's) and I have planted a lot of stuff so I have been watering every day or two for 15 minutes.

Since the leaves are turning yellow I have stopped watering with the sprinkler and I have been watering with a wand. It has rained a couple times this week so I haven't had to do any extra watering.

How deeply did you prepare the spot the rhubarb was planted in.
Rhubarb often needs DEEPLY, measured in feet with two being minimum, prepped soil as it needs well drained soil if the water does not run off due to slope.

Once established for three or more years it gets tougher but early on rhubarb is very fussy.

I have plants twenty plus years old but also have had seemingly healthy plants die after two years.

Wow! I certainly didn't go that deep. The hole was 12 inches or a little less and the prepared soil sits 2-3 inches above grade.

I'd make sure you don't have crown rot. Given that you're talking about new plants, the things that other have said are probably what's going on...but to be on the safe side, if you do dig it up, check to make sure the roots are very firm and not soft. I lost one rhubarb plant to crown rot, but I'm glad I figure it out before it spread to the others.

One way of greatly increasing your chances of success, is to rent a powered post hole digger, the wider the better.

Make the hole as deep as the machine will allow and fill the hole with commercial bagged manure.

Rhubarb roots go deeeeep, they will be to the bottom of that hole within five years which I found out when an unknown well I had --collapsed.
It left a hole over six feet wide and apprx. ten or so feet deep.
The roots of a rhubarb plant I had planted next to it six years earlier, the roots literally were on the edge of the hole, were within three feet of the bottom.