Season both sides of beef roast with salt and pepper. Add olive oil to a large skillet and place over MEDIUM-HIGH heat. Add roast and sear for a few minutes on each side, or until nicely browned. Remove from heat and transfer to 6 quart slow cooker.
Return skillet to heat add additional olive oil, if necessary. Add diced onion, celery, and minced garlic. Cook and stir for a couple of minutes and then and add red wine. Cook, stirring to deglaze the pan for just a minute or two and then transfer the contents of the skillet to the slow cooker with the roast. Scatter the carrots over the top and pour the diced tomatoes and tomato sauce around the roast.
Whisk together the beef broth, Dijon mustard, and Worcestershire sauce in a measuring cup or small bowl. Pour the mixture around the roast.
Sprinkle rosemary, thyme, basil, salt, and pepper over the roast and tuck a bay leaf into the sauce mixture.
Cover and cook on HIGH for 4 to 5 hours or on LOW for 7 to 8 hours. Slice against the grain and serve in chunks or shredded with the carrots and sauce. Garnish with fresh parsley, if desired.