Alex Smith looks to throw during the Redskins’ preseason loss to the Denver Broncos Friday night at FedEx Field. (John McDonnell/The Washington Post)

The Redskins preseason record dropped to 1-2 after a mostly dispiriting home loss to the Denver Broncos on Friday night. Here are the key takeaways:

Adrian Peterson stands out
All eyes were on Peterson, who made his Redskins debut after being signed off the scrap heap earlier this week, and the 33-year-old veteran didn’t disappoint. Peterson ran for seven yards on Washington’s first play from scrimmage, showed off his endurance on the Redskins’ next drive by rushing for 28 yards on seven attempts and later broke outside on fourth-and-one for a 15-yard gain.

“My legs were under me,” Peterson told Redskins sideline reporter Clinton Portis before halftime. “I felt good.”

He looked good, too, finishing with 56 yards on 11 carries. Peterson’s durability will be a concern for the remainder of his career, but assuming he’s still healthy, it’s hard to imagine he’s not the starter against the Cardinals come Week 1.

Alex Smith, Colt McCoy struggle
Outside of Peterson, the Redskins’ offense was mostly nonexistent for three quarters. Alex Smith, who sat out Washington’s first preseason game and played only one series last week, looked rusty.

Smith started and played most of the first half, finishing 3 of 8 for 33 yards. At times, it appeared Smith only had eyes for tight end Vernon Davis, though he managed to hook up with Paul Richardson for a couple of completions on his final drive. Somehow, backup quarterback Colt McCoy’s night was even uglier — he lost nearly as many yards (15) on two sacks as he gained on his three completions (19). Kevin Hogan led the Redskins to a pair of fourth-quarter touchdowns.

Tackling woes
There’s no telling exactly how many yards Peterson would have gained were he going up against the Redskins’ defense on Friday, but it would’ve been more than 56, that’s for sure.

After a strong performance against the Jets last week, Washington’s defense struggled against the Case Keenum-led Broncos in the first half. The Redskins failed to generate much of a pass rush, allowed the Broncos to complete three of their six third downs before halftime and missed multiple tackles on both of Denver’s first-half touchdowns, including a 27-yard end-around by wide receiver Emmanuel Sanders.

Third down and out
Third downs were a problem for the Redskins last season, when their 32.4 percent conversion rate was second-worst in the league. Washington was a putrid 1 for 11 on third down against the Broncos. The Redskins’ only third-down conversion didn’t come until the fourth quarter, when a Rob Kelley run helped set up Hogan’s touchdown pass to Simmie Cobbs Jr.

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Updates and analysis

Final score: Broncos 29, Redskins 17

Something to build on: Kevin Hogan has had, by far, the best night among the Redskins’ three quarterbacks. The former Gonzaga High standout capped his second consecutive drive with a touchdown pass to Darvin Kidsy with 25 seconds remaining. Hogan is 7 for 9 for 88 yards and two scores.

Five for five: Brandon McManus’s fifth field goal with 2:31 remaining extended Denver’s lead to 29-10.

At long last, a Redskins touchdown: Washington’s first touchdown since the second quarter of the preseason opener came with 10:44 to play in the fourth quarter on Friday. McLean native Kevin Hogan, who came on in relief of Colt McCoy, found Simmie Cobbs Jr. for an 18-yard strike to cap an impressive 78-yard drive that cut the Broncos’ lead to 26-10.

Brandon McManus . . . from downtown: With 14:13 to play in the game, Brandon McManus drilled his fourth field goal, a 56-yarder that extended the Broncos’ lead to 26-3. McManus would like to remember this night. The Redskins’ offense not so much.

Colt McCoy banged up?: Trainers checked on McCoy following yet another three-and-out late in the third quarter after he appeared to have his right thumb bent back on a sack. Entering the fourth quarter, McCoy was 3 for 8 for 19 yards.

Broncos add another field goal: Brandon McManus’s third field goal of the night, a 34-yarder with 4:07 remaining in the third quarter, gave Denver a 23-3 lead.

Redskins’ offense continues to struggle: Washington’s first possession of the second half ended with Tress Way’s fifth punt. The Redskins are still looking for their first third-down conversion.

Broncos extend their lead to 20-3: Chad Kelly replaced Case Keenum at quarterback to start the second half and led the Broncos on a 10-play drive capped by a Brandon McManus field goal. Former Virginia Tech standout Adonis Alexander, who is making his preseason debut for the Redskins, made a nice recovery to break up a pass intended for fellow rookie DaeSean Hamilton on the drive.

Halftime: Broncos 17, Redskins 3. Denver takes a two-touchdown lead into the break, thanks to quarterback Case Keenum (12 for 18, 148 yards) and Emmanuel Sanders (88 total yards and a touchdown). Adrian Peterson shined with 56 yards on 11 carries in his Redskins debut, but Washington’s offense has otherwise struggled. The Redskins are 0 for 7 on third down.

Sack party: Anthony Lanier forced a punt on the Broncos’ final drive of the first half by bulldozing his way into the backfield for a sack of Case Keenum on third down. Denver returned the favor on Washington’s ensuing drive, when rookie Bradley Chubb and DeMarcus Walker combined to drop Colt McCoy for a six-yard loss.

Adrian Peterson assesses his debut: “It was good to get out there and knock some of the extra rust off, but I felt good,” Peterson told Redskins sideline reporter Clinton Portis after rushing for 56 yards on 11 carries before halftime. “My wind, my conditioning, my legs were under me. I felt pretty good.” Portis, who joked that he was angry when Peterson decided to wear his old No. 26, then presented Peterson a signed “Portis” Redskins jersey. Classic.

Alex Smith’s night is done: Yuck. Smith completed his last two throws, but was 3 for 8 for 33 yards when he was replaced by Colt McCoy late in the first half.

No answer for Emmanuel Sanders: The Broncos’ receiver single-handedly shredded the Redskins’ struggling defense late in the first half. One play after making a 15-yard catch for a first down on third-and-long, Sanders beat Fabian Moreau for a diving, 33-yard reception. He capped Denver’s six-play drive with a 27-yard touchdown run on an end-around that featured several missed tackles. With 4:37 to play, the Broncos led 17-3.

Redskins get on the board: Dustin Hopkins’s 33-yard field goal with 8:11 to play before halftime cut the Broncos’ lead to 10-3. The kick capped a 10-play, 63-yard drive that featured a pair of Alex Smith completions to Paul Richardson for 31 yards and a whole lot of Adrian Peterson. Because it’s the preseason, the Redskins went for it on fourth-and-short from their own 41 early in the drive and gave the ball to Peterson. Rather than dancing in the backfield or crashing into the line for no gain as Washington’s rotating cast of running backs did so often in short-yardage situations last season, Peterson bounced the play to the outside for a 15-yard gain. With 11 carries for 56 yards, he has looked like the Redskins’ best player on the field.

Three-and-out: Alex Smith has looked rusty in his first extended action of the preseason. The Redskins’ quarterback, who sat out the first game and played one series last week against the Jets, overthrew Kapri Bibbs and Vernon Davis on the first two plays of Washington’s third drive and failed to connect with Davis on third-and-long. After one quarter, Smith is 1-for-6 for two yards. He’s also been sacked once.

Broncos take 10-0 lead on TD run by Royce Freeman: With 39 seconds remaining in the first quarter, Denver rookie running back Royce Freeman burst through the line and shook off would-be tackles by safeties D.J. Swearinger and Montae Nicholson for a 24-yard touchdown run. The Redskins’ tackling has left something to be desired thus far.

More to like from Adrian Peterson: Peterson got the call on the first two plays of the Redskins’ second drive. He was stopped for no gain on the first, but made a nifty cut on the second to set up a 13-yard gain.

“He looks like he’s a young AP right now,” Redskins Broadcast Network sideline reporter Clinton Portis said after a four-yard Peterson run a few plays later.

Washington’s drive ended when Vernon Davis was tackled after a 2.5-yard reception on fourth-and-3, but Peterson was up to 35 yards on eight carries. That’ll do.

Broncos take a 3-0 lead with 8:00 to play in the first quarter: Denver mounted an 11-play drive on its first possession, but Redskins cornerback made a nice play to break up a Case Keenum pass intended for Emmanuel Sanders to force the Broncos to settle for a 50-yard Brandon McManus field goal.

A solid first impression: The Redskins won the toss and elected to receive, giving everyone an early look at the first-team offense featuring Adrian Peterson. The newly signed 33-year-old running back received the handoff from Alex Smith on Washington’s first play from scrimmage and ran seven yards up the middle. Heck of a signing. Smith was sacked on second down and Vernon Davis dropped a pass along the sideline on third and long, but there was a lot to like about Peterson’s first carry. Just don’t pencil him in for a 2,000-yard regular season just yet.

Preview

As is customary for the third preseason game, Washington’s starters are expected to play more in Friday’s home exhibition against the Broncos than in any other tuneup before the regular season. Most of the focus will be on the Redskins debut of running back Adrian Peterson. The 2012 NFL MVP was signed Monday in the wake of rookie Derrius Guice’s season-ending injury, along with less serious injuries to running backs Samaje Perine and Byron Marshall. Friday represents the 33-year-old Peterson’s first chance in a game setting to show Coach Jay Gruden — and Redskins fans — that he still has something left in the tank after averaging 3.4 yards per carry with the Saints and Cardinals last season.

Gruden has already announced that tight end Jordan Reed and running back Chris Thompson won’t play against the Broncos. Receivers Maurice Harris, Cam Sims and Brian Quick are all out, while Jamison Crowder will be a game-time decision. Trent Williams is expected to make his preseason debut.

Quarterback Alex Smith, who sat out Washington’s first preseason game and played only one series in the Redskins’ 15-13 win over the Jets last week, figures to get a few more reps. Smith’s counterpart, former Vikings quarterback Case Keenum, is 9 for 17 for 83 yards in two preseason games after signing a two-year deal with Denver during the offseason.

It’s unclear how much Washington’s defensive regulars will play.

“We need all the work we can get, all the work that [Gruden] allows us to get,” safety D.J. Swearinger said. “After this week, it’s live bullets when we go to [Arizona]. It’s always good to get that real field work, the real game experience so we can be ready September 9.”

Washington Redskins vs. Denver Broncos
Kickoff: 7:30 p.m., FedEx Field
TV: NBC 4, NBC Sports Washington
Stream: NBCSports.com, NBC Sports App
Radio: 980 AM; 105.9 FM

Pregame reading

Adrian Peterson tops the list of reasons to watch Redskins-Broncos

Redskins get serious ahead of third preseason game

Jay Gruden just as anxious to see Adrian Peterson’s debut as the fans

Clinton Portis says Adrian Peterson wearing No. 26 shows ‘a lot of respect’

Kapri Bibbs says he loves having Adrian Peterson as a teammate

Analysis: Projecting the Redskins’ 53-man roster, including Adrian Peterson

First glimpse of Alex Smith reveals a QB aware of all his options

Analysis: Why Adrian Peterson isn’t a great fit for the Redskins’ offense