My take on a roller bearing at the rod big end is this:
1) If it seized such that the rod bent, you'll know it. The rod won't freely rotate around the crank - It'll stick at worst and be "chunky" at best
2) If the piston took a hard enough hit to bend the rod, one of the races of the needle bearing is probably brinnelled and destined for failure anyway (crank is the inner race, rod is the outer race). Brinnelling occurs when a load through the bearing is high enough that the needles, or other rollers, actually indent the surface of the shaft or outer race. (If it's there, it's easy to see: marking on one or both of the races (usually the inner) at roller spacing. If it's really bad, you can feel it.) Once that occurs, it's only a matter of time before surface fatigue starts at the 'bumps' and progresses to bearing failure.
If it's a roller bearing rod, it's been hardened to function as a bearing raceway. That surface hardening may just be in the bore, but it could extend to the rod itself. If you heat the rod to straighten it, the case may temper back and lower the strength of the rod.
All of this is conjecture, but they are things to consider. If it is a journal bearing rod, like our 'bolts, none of this is relevant.
