Can a hard drive fix itself

Cybernetics SAN, 8 500gb drives, RAID 5 w/hot spare. Drives are S.M.A.R.T.
Hosting 5 virtual servers.

At 3:20 this morning I got a text of a drive issue: "ERROR - Drive timeout
detected: port=5"

Talked to the hardware guy at that time. He checked in and said the RAID 5
was still functioning and the hot spare was still available. Suggested we
wait till business hours since there was a hot spare.

Around 9am we decided we would do the replacement around 4:30pm since
things would be a lot less busy for the RAID 5 rebuild. The RAID 5 was
still functioning and if one didn't drill down in all the way, you wouldn't
even see the status DEVICE ERROR on that drive.

I checked it out about an hour ago and the DEVICE ERROR is gone, replaced
by OK which is what it should say. Hardware guy says he has seen this
before simply by reseating the "problem" drive.

But we did no such thing. Haven't touched it at all. Hardware guy
suggests waiting a day and see what happens.

Anybody seen this before? A drive heals itself?

Thanks.