Place all the vegetables except for the chipotles and garlic in a large roasting pan that has been coated with a little oil. Pam is fine.
Season the buffalo with some salt and pepper, and place it on top of the vegetables.
Add the diluted beef stock and roast the buffalo at 250° F for 2½ hours or until the meat reaches an internal temperature of 125° F.
Remove the pan from the oven and the roast from the pan and let it sit, covered with foil, while you work on the sauce. Remember, the roast will continue to cook while it is resting.
Transfer the roasted vegetables to a bowl or plate and put the roasting pan on the stove over medium-high heat, across two burners if necessary.
Add the roasted garlic, peppers and red wine to the sauce pan and stir and scrape to deglaze the pan.
Reduce the liquids by about ⅓ and strain it to remove the garlic and peppers.
Taste for seasonings and adjust with salt and pepper.
Slice the buffalo roast and serve with the roasted vegetables and au jus sauce.