Rashad Jennings

The Giants' running game was bottled up by the Bills in Saturday's preseason game. (Brett Carlsen/Getty Images)

The Giants' first-team offense was a disaster in Saturday's 21-0 loss to the Bills in the second preseason game. Many of the problems stemmed from woeful blocking up front from the offensive line and tight ends.

"Our run blocking unit needs to improve assignments, fundamentals, and physicality," coach Ben McAdoo said after his offense managed 10 yards on eight carries in the first half of Saturday's game.

The passing game wasn't much more effective, as starting quarterback Eli Manning completed just 4-of-9 passes for 44 yards in four drives.

Before analyzing what went wrong (and, in a few instances, right) on each of the first-team offense's 16 plays, here are a few takeaways:

*Manning could have helped his line on a few incompletions, but he hurried a couple of throws and didn't set his feet after avoiding the rush.

*Penalties were a killer. Left tackle Ereck Flowers and center Weston Richburg were flagged for holding penalties on the first play of consecutive drives. Not surprisingly, the Giants went three-and-out both times they were backed up on first down.

A false start by right guard John Jerry turned a third-and-6 into a third-and-11 on the Giants' opening drive. The Giants turned the ball over on downs two plays later.

*The horrible blocking efforts by top tight ends Larry Donnell and Will Tye should help the cause of Will Johnson, who missed the game with a stinger. Donnell and Tye often lined up in the backfield, sometimes together in an inverted wishbone. Johnson, who is a more natural H-back, could be a better fit in that position assuming he is able to return to practice in the near future.

Here's a play-by-play breakdown of the 16 plays (not including two penalties) with Manning on the field:

FIRST DRIVE

1-10 at NY 37: Rashad Jennings runs for -1 yard

Jennings ran up the middle and was instantly met by a wall of defenders. The left side of the line got no push. Flowers and Donnell, who was lined up on the line, were beat inside, which gave Jennings nowhere to run.

2-11 at NY 36: Shane Vereen runs for -1 yard

With Tye and Donnell lined up in front of Vereen in an inverted wishbone, Vereen took a handoff to the right side. Right tackle Marshall Newhouse ran past outside linebacker Jerry Hughes and Tye went inside to the second level. No one picked up Hughes and the play was blown up in the backfield. Newhouse and Tye had an obvious miscommunication, which they spoke about after the play.

3-12 at NY 35: Manning completes 22-yard pass to Odell Beckham, Jr.

The Bills rushed four and the line gave Manning a clean pocket to deliver a quick slant to Beckham for a 22-yard gain.

1-10 at BUF 43: Vereen runs for -1 yard

Lined up on the right side of the line, Donnell missed a block on Hughes. Donnell demonstrated terrible technique on the play, as Hughes easily beat him inside to meet Vereen deep in the backfield. The worst part of Donnell's failure is that Jerry and Newhouse had sealed their men inside and there was a chance for a nice gain.

2-11 at BUF 44: Manning completes 5-yard pass to Tye

Manning hit Tye on a quick dump-off in the right flat for five yards. Flowers allowed a little pressure from the backside, but it didn't affect the quick-hitting play.

3-11 at BUF 44: Manning completes 9-yard pass to Tye

After a false start on Jerry, the Bills brought four rushers on third-and-long. Manning hit Tye on a quick out to the right side for nine yards. The left side of the line was setting up a screen for Vereen that looked like it could have been a big gain.

4-2 at BUF 35: Manning incomplete to Beckham

McAdoo elected to go for it on fourth-and-short and Manning took a shot downfield to Beckman running a double-move. The line provided excellent pass protection, but Manning's pass was slightly overthrown. There could have been a penalty on Buffalo cornerback Stephon Gilmore for illegal contact/holding.

SECOND DRIVE

1-20 at NY 10: Jennings runs right for 1 yard

After a Flowers hold on first down, Jennings ran up the middle. Newhouse and left guard Bobby Hart were both beat inside, which clogged up the middle and gave Jennings nowhere to run.

2-19 at NY 11: Manning incomplete to Sterling Shepard

The Bills overloaded the left side with five rushers. Flowers was beat around the edge, which forced Manning to step up into some pressure. Tye, lined up as the H-back, provided a weak block on a blitz pick-up. Manning's pass to Shepard on a crossing route was low. Manning could have made a better throw, but he was under pressure and Shepard was well-covered. Jennings was open for an easier pass after releasing late.

3-19 at NY11: Jennings runs for 11 yards

Jennings ran hard up the middle on a draw, but the 11-yard gain was hollow on third-and-long.

THIRD DRIVE

1-20 at NY 20: Andre Williams runs for 4 yards

After a Richburg hold on a first-down run that featured another Donnell whiff, Williams carried up the middle. Newhouse was beat around the edge, forcing Williams to cut left. Jerry missed the linebacker in the hole while pulling and Donnell couldn't seal his man inside. Give Williams credit for making something out of nothing.

2-16 at NY 24: Manning incomplete to Beckham

There was a little bit of pressure from the right side, but this appeared to be a designed quick pass. Manning was simply off the mark as he rolled right on a pass to Beckham on the sideline.

3-16 at NY 24: Manning sacked for 9-yard loss

The Bills only brought four rushers, but breakdowns by both tackles led to a sack. Newhouse was pushed straight backwards, which forced Manning to try to escape the pocket, but Flowers was beat outside so Manning wisely took a sack. Manning couldn't step up in the pocket because Hart was beat inside.

FOURTH DRIVE

1-10 at NY 25: Manning incomplete to Tye

Manning rolled right after a play-fake and made a bad pass behind Tye running an out to the right flat.

2-10 at NY 25: Manning completes 8-yard pass to Tavarres King

Manning had a clean pocket against a five-man rush and he delivered a quick slant to Tavarres King. The receiver made a nice diving catch on the low throw for an eight-yard gain.

3-2 at NY 33: Manning incomplete to Roger Lewis

The Bills only brought three rushers. Manning wanted to throw a quick out to Tye on the left side, but he pumped after realizing the Bills were sitting on that route. Manning came back to his right and stepped up past the rush. Lewis adjusted his route and went deep when Manning started to move in the pocket. Manning had time to set his feet, but he rushed an errant deep pass to Lewis, who seemed to lose track of the ball. Manning could have dumped a pass to Jennings in the middle for an easy first down.

Dan Duggan may be reached at dduggan@njadvancemedia.com. Follow him on Twitter @DDuggan21. Find our Giants coverage on Facebook.