The plus for PIT would be years of team control, but if they don't want Chavis, I can understand why.
For what it's worth, BTV has Frazier valued at 4.5. He has 2 years of team control, which might overlap with Downs, but we could alsways trade him, once we know Downs is for real and ML ready. (Word is LH's RP'er Brault ison the market, too at a 1.8 value)
Here are some possible combinations of values that would come close to 4.5:
6.6 Chavis (in theory could get Frazier and Brault- maybe throw in Brice or Taylor)
6.0 Lugo
5.2 Groome
4.6 Song
3.7 Wong
3.6 Murphy
3.1 Decker
2.9 Bonaci,Potts & Jordan
2.5 Arauz
2.2 Lopez & Gonzalez
2.1 Ramirez
2.0 Bello, Cannon, Cacon, Rafaela
I'd give 2 from Decker, Arauz & Murphy for 2 years of Frazier and 3 years of Brault.
I'd give Arauz & Cannon for Frazier.