The X Factor | 2021 Week 1 vs. San Francisco 49ers 1 min read 3 years ago By: Detroit Lions Watch More at Detroit Lions Share this:TwitterFacebookLinkedInPinterestRedditTumblrWhatsAppPocketPrintLike this:Like Loading... Related Tags: 2021 49ers detroit Detroit Lions factor francisco lions NFC NFL san the Video. YouTube Videos vs. week YouTube Continue Reading Previous Colts remain 2.5-point underdogs vs. Seahawks in Week 1Next John Harbaugh: We’re Back in the Fight | Baltimore Ravens