FOXBOROUGH, Mass – The New England Patriots visit the Detroit Lions on Friday night, and here are the main things I think would make the night a success for the team.

David Harris collected four tackles last week against the Texans, and can further make his case Friday against the the Lions. Daniel Dunn/Icon Sportswire

1. No injuries. This is always No. 1 on the list. This is the last time most of the team’s top players will be in action this preseason, as the focus will quickly shift to the regular-season opener Sept. 7 against the Kansas City Chiefs. Some older Patriots fans recall the 1989 preseason when Andre Tippett, Ronnie Lippett and Garin Veris were lost to season-ending injuries in the final preseason game. Those types of injuries to key players can change the outlook of a season.

2. Another step for David Harris. This should be a good night to evaluate how Harris, the veteran middle linebacker, is doing in his transition from the Jets to the Patriots. With linebackers Dont’a Hightower, Elandon Roberts and Shea McClellin not making the trip to Detroit, it could mean that Harris gets the start in the middle. He played 24 snaps in Saturday’s preseason loss to the Texans and was credited with four tackles. Harris is expected to be a significant part of the Patriots' defensive plans, and how he looks Friday night should provide a feel for how realistic that expectation is.

3. Getting Mike Gillislee in the mix. After saying he had an MRI on his hamstring come back clean, and that he was a full participant in practice, Gillislee could be primed for his preseason debut. Dion Lewis and Rex Burkhead have run the ball effectively, and Gillislee should too. Getting him at least a few carries before the opener would be a positive for the team.

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4. Building up conditioning another notch. The Patriots traditionally increase the playing time of their first-stringers through the first three games of the preseason, which helps them building a strong conditioning base. That sometimes means playing into the third quarter in the third preseason game, as players get a feel for what it’s like to come out of the locker room at halftime and play at least one more series. Bill Belichick often says that preseason is about preparing for the 16-game regular season, with a high priority on the season opener. Conditioning is a big part of that.

5. Tighten up on big plays defensively. While some of them involved players who won’t be on the initial 53-man roster, and there was no scheming involved, the Patriots have given up too many big plays on defense in the first two games of the preseason. Cornerback Malcolm Butler, for example, was involved in one big passing play last Saturday. Tightening up in that area would help the defense build some positive momentum into the regular season.