But we believe the Patriots not only see Harrison as a helpful addition at a need position, with the team thin at the "edge" spots — the team had to pick up Eric Lee there, is featuring fourth-round rookie Deatrich Wise heavily and has moved linebackers (such as Trevor Reilly, who was released to make room for Harrison on the roster) into that role.
This also could be a signing with the Patriots' first playoff opponent in mind. If the Patriots can clinch the top spot in the AFC, there's a chance they could face the AFC West champion Kansas City Chiefs, the team that stunned them in Week 1. And though the 39-year-old Harrison hasn't played much this season, he has had a history of dominating Chiefs left tackle Eric Fisher.
Harrison's most extended action this season came in Week 7 against the Chiefs, when he logged 18 of his 38 snaps on defense this year. Harrison provided a late sack and a handful of pressures to help the Steelers win and prevent a late Chiefs comeback. And in January, Harrison also had a sack and later drew a key hold against Fisher with a strong pass-rush move at game's end as the Steelers held on for a postseason victory at Arrowhead Stadium.
Prior to the Week 7 game this season, Steelers defensive coordinator Keith Butler said he wanted to feature Harrison in an expanded role because “it’s always good to have James Harrison when you’re playing Kansas City and let the offensive tackle [Fisher] see him.”
Additionally, the Patriots' coaches took note of the Fisher hold and used that play — with the same officiating crew as the Chiefs-Steelers playoff game — to exploit Falcons left tackle Jake Matthews at the end of Super Bowl LI. Surely, the Patriots know all about Harrison, who has faced the Patriots 10 times in the Belichick-Tom Brady era. But that matchup with Fisher had to be fresh in their minds.