David Wells Statistics @ theHILLRumor has it that the Rangers are looking at David Wells for some minor league hitters. It makes sense from the Rangers point of view as they could use some pitching.
I went through theHILL and ran a report for Wells from 1990-2000 with his starts separated by month. His worst two months for ERA are August and September, but his best is July. I'm guessing that he pitches best in warm weather, when he isn't rundown from extended warm weather. The trouble with Texas is that he'll get rundown pretty quickly. Here are some more stats, also from
theHILL. For his career, he has a 5.63 ERA at home against Texas and a 4.97 ERA at Texas, so that doesn't show much of a problem with the heat.
I wouldn't worry about the heat too much if I were Doug Melvin. I would worry if he tips the scales much over 300 pounds.