I doubt that Chapman is on the radar. At this point in his career, I'm not sure if I'd want him...a lot of it would just depend on what else we did to address the bullpen. Looking at offseason moves individually is a bit myopic, you have to look at the whole picture.
If Chapman is the only bullpen piece we pick up, I'm probably not too happy about that. If he's part of a group of 3+ guys that all bring something to the table and the bullpen looks like an overall upgraded unit.
He's not nearly what he used to be, he's not as invincible as he was...I'd hesitate to call him a weapon. But compared to the Givens pickup last year which turned out to be a massive flop, I think he'd be alright. Not great, not terrible, just alright. Probably a net positive but not a huge difference maker by himself.