One week, Miami's Jay Ajayi gained 214 yards rushing against Buffalo. The next, New England quarterback Tom Brady piled up 315 yards and four touchdowns passing.
Ryan also didn't provide updates on running back LeSean McCoy, who did not play against New England because of a left hamstring injury, or backup Reggie Bush, who hurt his groin on Sunday.
"We know we have to play better, and especially against an opponent like that," Ryan said Monday, a day after Buffalo gave up five touchdowns in a 41-25 loss to New England . "What was really disappointing to me is that we played poorly, it's as simple as that."
It was the Bills inability to stop the Patriots on third down that stung Ryan most.
This isn't what Ryan expected from a unit he vowed would be much improved over last season's high-priced defense, which finished 19th in the NFL in yards allowed. It was the worst end-of-season ranking in Ryan's 11 seasons as a coach or coordinator.
The numbers don't look much more promising halfway through this season with the Bills (4-4) preparing to travel to Seattle for a prime-time showdown on Nov. 7. Buffalo is 16th in yards allowed per game at 360.3, including 25th in rushing yards allowed per game with 118.4.
In the first half alone, Brady completed 6 of 6 attempts for 111 yards with two touchdowns and was sacked twice on third down. One of his touchdowns was a 53-yarder up the left sideline to Chris Hogan on third-and-13.
In those four wins,Cheap Jerseys Online, Buffalo combined to allow four touchdowns, force 10 takeaways (four fumbles and six interceptions) and limit opponents to converting 13 of 52 third-down chances.
Without being specific, Ryan made what he called "a tactical mistake" in departing from his game plan once Buffalo's top pass-rushing threat, linebacker Lorenzo Alexander, was sidelined by a hamstring injury during a punt return early in the second quarter.
If he can't play, rookie first-round pick Shaq Lawson will have to fill in. Lawson has played limited time the past two games and had been out since having surgery to repair a shoulder injury in May.
"We can't win like that. There's no way. We've got to be smart," Ryan said. "If we get beat physically, that's one thing. But when you contribute to some of the mistakes or some of their big plays, we have to get better."
Ryan didn't have an update on Alexander's status.
ORCHARD PARK, N.Y. (AP) — Bills coach Rex Ryan is having difficulty assessing why his prized defense is playing so inconsistently.
Ryan also regretted the decision to continue having Alexander play a dual role on defense and special teams.
"I know I can do better," he said.
In losing the past two games, Buffalo has surrendered a combined 811 yards offense and eight touchdowns without managing a takeaway.

"That's inexcusable,Cheap Jerseys Wholesale," Ryan said.
Brady converted New England's first five third-down opportunities and nine of 12 overall before giving way to backup Jimmy Garoppolo in the fourth quarter.
That's a departure from how productive the defense played during a four-game winning streak that ended with a 28-25 loss to Miami on Oct. 23.
Against New England, Lawson had his first career sack but was also flagged for roughing the passer on a third-and-7.
In four losses,Cheap NFL Jerseys, Buffalo has given up 13 touchdowns, forced just two takeaways (both fumbles) and had opponents convert 28 of 53 third-down chances.
The 33-year-old Alexander entered the game with an NFL-leading nine sacks, doubling the number he had in his first nine seasons.
Things didn't get much better in the second half,Wholesale Jerseys, when the Patriots converted three third-down opportunities because of penalties,Wholesale Jerseys 2017, including Buffalo being flagged for having 12 men on the field.
The coach took some of the blame.
NOTES: A few days after cutting Ed Eagan, the Bills signed the receiver and TE Manasseh Garner to their practice squad. ... After playing Seattle, the Bills enjoy a break in entering their bye week off.