Five 49ers to watch in crucial regular-season showdown vs. Seahawks in Week 18

The 49ers kicked off the regular season 17 weeks ago against the Seattle Seahawks.Now, the playoff-bound teams close out the season with the NFC West title, a first-round bye and home-field advantage throughout the playoffs at stake.“Give the schedule-makers a lot of credit for bookending those two games and having the foresight to have a game like this at the end of the year,” general manager John Lynch quipped on 49ers Game Plan.“It’s going to make for great theater, and it’s fun to be a part of.”The 49ers won the first meeting between these teams, 17-13, on Sept. 7 in Seattle.And in order for the 49ers to achieve the season sweep, here are five players who must come through with strong performances:RB Christian McCaffreyThis is the final chapter in what has been a remarkable regular season for Christian McCaffrey, who was sidelined for all but four games last season with injuries.McCaffrey, who was limited in practice this week due to back tightness, enters this game with 1,179 yards and 10 touchdowns rushing. He also has 96 catches for 890 yards and seven touchdowns.McCaffrey is heating up on the ground. He has averaged 4.5 yards per...