I am getting a number of calls on rolling fields after the snow melt. Bottom line, if the field is wet (ie - you can hear and or see water on the turf) DO NOT roll the field. I drove by a field this morning that had standing water in the outfield and it was being rolled with a 1 1/2 ton roller. Rolling a field when completely saturated has a great chance of causing serious compaction issues.
HERE is a great article about rolling athletic fields from Buckeye Turf notes from Ohio State.
Go to j-dturf.com to learn more about J&D Turf.