FOXBOROUGH -- The mantra of the New England Patriots when a player gets injured is "next man up."
This week that man will be backup linebacker Dane Fletcher.
With Brandon Spikes joining three key defenders on injured reserve with a knee injury, Fletcher is likely to see a lot more action when the Patriots host the Indianapolis Colts in an AFC divisional-playoff game Saturday night.
"Everybody has to step up," Fletcher said Tuesday. "Everybody's role kind of increases on defense, especially in the linebacker unit."
Spikes, an outstanding run stopper in his fourth season, was placed on injured reserve Monday.
That left the Patriots with six linebackers on their 53-man roster, including rookie free agent Ja'Gared Davis, who was signed off the practice squad Tuesday. Two others have played very little on defense. Rookie Steve Beauharnais has one tackle in two games and Chris White has one defensive tackle while being used mostly on special teams.
The remaining starters are Don't'a Hightower and rookie Jamie Collins, a first-round draft choice.
Fletcher, a better pass defender than Spikes, has averaged just 14 defensive snaps in the 15 games he's played, starting just one. He played more than half the snaps only once, against Denver and Peyton Manning.
"Spikes has done a great job this year," safety Devin McCourty said, "being a guy that's been a leader on the defense, a guy that's stepped up and made key plays, I think, like he's always done, but really stepping into a leadership role.
That figures to be Fletcher.
"Every play matters. Every second you're in there matters," he said. "It could be one problem play that costs your whole team so you don't want to be that guy. So it's just kind of that time of the year where everything amps up in every aspect of the game."
New England has played most of the season with three of its best defensive players on injured reserve. Tackle Vince Wilfork played the first four games, tackle Tommy Kelly played the first five and linebacker Jerod Mayo played the first six.
The Patriots did well enough without them to earn a first-round bye.
But will the latest injury be one too many?
"I hope not," McCourty said with a laugh.