Two of the NFL's most iconic franchises renew one of the league's most storied rivalries when the San Francisco 49ers host the Dallas Cowboys in the Week 8 Sunday Night Football Game at Levi's Stadium in Santa Clara, Calif. Both the 49ers and the Cowboys have won five Super Bowl titles. That's tied for the third most all-time, one behind the Patriots and Steelers. San Francisco and Dallas have met 40 times, including the playoffs. The 49ers hold a slight 20-19-1 edge and have won the last three meetings, which have come in each of the last three seasons.  For Sunday, San Francisco is a 4.5-point favorite in the latest 49ers vs. Cowboys odds, while the over/under is 47. Kickoff is set for 8:20 p.m. ET.

This season, however, has not gone as well as San Francisco and Dallas fans hoped. The 49ers entered the season as the reigning NFC champions, but injuries and inconsistency have contributed to a 3-4 record. After losing to the two-time defending Super Bowl champion Chiefs last week, San Francisco sits in the basement of the NFC West. Meanwhile the Cowboys (3-3), who were blown out by the Lions 47-9 prior to their bye week last week, are in third place in the NFC East, ahead of only the Giants.

The 49ers offense figures to have a plus matchup against the Dallas defense. The Cowboys give up 28.0 points per game, which is the second most in the league. In addition, the defense may be without star linebacker Micah Parsons, who is dealing with an ankle injury that forced him to miss the last two games. 

However the San Francisco offense is dealing with injuries of its own. Running back Christian McCaffrey (Achilles) has been on injured reserve all season and will not play on Sunday. Receiver Brandon Aiyuk tore the ACL and MCL in his right knee in last week's loss to Kansas City and is out for the rest of the season. Other key skill position players—running back Jordan Mason (shoulder), receiver Deebo Samuel (pneumonia), tight end George Kittle (foot sprain) and receiver Jauan Jennings (hip)—are all nursing various ailments. 

Meanwhile the Dallas offense has been hampered by a punchless running attack and the turnover bug. The Cowboys have the worst rushing attack in the league, averaging just 77.2 yards per game and 3.5 yards per carry, which both rank last in the NFL. On Sunday they will face a 49ers defense that was gashed by Kansas City's rushing attack for 184 yards and four touchdowns last week. 

Dallas also has committed 11 turnovers this season; just three teams—the Raiders (16), Titans (12) and Panthers (12)—have committed more. Quarterback Dak Prescott has thrown two interceptions in each of the Cowbows' last two games. That does not bode well against a San Francisco defense that has forced 13 takeaways this season, tied for the third most in the league.

We'll take you through every aspect of the 49ers-Cowboys Sunday night game that you need to know before you lock in your bets, including SportsLine expert picks, props, trends, injury information and everything else that will help you know which plays are worth making for the primetime matchup. 

Who wins 49ers vs. Cowboys in the Sunday Night Football game, and what critical X-factor makes one side of the spread hit? Join SportsLine right now to see everything you need to know about the Week 8 Sunday Night Football matchup.