Today around noon I went to Richmond Airport (RIC) to do some spotting, but I only saw three planes: a United A319 and two Delta MD-88s. One of the MD-88s, N914DL, had the right engine opened up and mechanics were working on it. The flight was supposed to have departed for ATL at 10:50 AM, and it was now a little after noon. There was a long line of people trying to get rebooked. Later today, around 4:45 PM, I decided to check out DL 2283 on THE TRIP's flight tracker. It showed the flight finally left RIC around 4:30 PM and was due in ATL around 5:50 PM. While I was watching the flight approach ATL, I saw it turn around, and the destination changed to Knoxville. It was to arrive around 6:10. I checked the weather in ATL to see if that was the cause of the diversion. The weather was fine. I continued to follow the flight, and it landed in Knoxville a little after six. I called Delta and asked about the flight, and they said it was diverted to Knoxville due to a mechanical problem. I wonder if it was another problem with the same engine I saw them working on in RIC. If they were approaching ATL, why would they suddenly turn around and go to Knoxville? Since Delta's major hub is ATL, it looks like they would have more mechanical support there. Does anybody have any details on this?