Josh Doctson, coming off an injury-plagued rookie season, was impressive in the Redskins’ first practice of training camp. (John McDonnell/The Washington Post)

RICHMOND — The Washington Redskins held their first practice of training camp Thursday and appeared to get in some quality work on both sides of the ball. Players seemed to pick up right where they left off in June at minicamp, which proved encouraging to coaches and players.

Here are three things we learned on Day 1 of training camp, plus a few other odds and ends:

1. Competition on defense: There seems to be more competition on defense than in any of my eight years covering Redskins training camp. There is very little clarity on the direction Greg Manusky and Jim Tomsula are leaning for their defensive line or whom Manusky and Kirk Olivadotti prefer at inside linebacker.

For now, it looks as if three D-line jobs and possibly both inside linebacker spots are up for grabs. As he did during the spring, Joey Mbu lined up as the starting nose tackle. Ziggy Hood started at left end and Terrell McClain at right end. This is a change. Though Hood got first-team work during the spring, McClain (signed as a free agent) did not. Later, A.J. Francis replaced Mbu at the nose, and Matt Ioannidis and Stacy McGee played end. For nickel packages, Anthony Lanier and Jonathan Allen took some snaps.

Another guy to keep an eye on: nose tackle Phil Taylor. The former Cleveland first-round pick hasn’t played since 2014 because of injuries and has worked primarily with the second and third units. But once he’s up to speed, he could make an impact.

Based on how they were acquired, it would seem that Allen (17th overall pick), McGee (five years, $25 million) and McClain (four years, $21 million) would be the favorites to start. But those three have yet to share the field. Tomsula was really impressed with how hard Mbu worked during the offseason, and that’s why he’s giving him a crack at nose tackle. A number of the offensive linemen have praised him and think he’s the best option. But it’s still super early.

Tomsula will rotate guys with great frequency, so it might not even matter who starts. One thing is certain: By mixing it up so much in practice, Tomsula is stoking those competitive fires.

Inside linebacker seems a little less uncertain. Will Compton, Mason Foster and Zach Brown all rotated during the spring. Sometimes it was Compton and Foster, Foster and Brown or Compton and Brown. But Compton spent most of Thursday as the “Mike” rather than rotating with the others. It was Foster and Brown who rotated as Compton’s sidekick. Compton has drawn praise for his leadership and communication, possibly giving him an edge. Brown lined up next to Compton during the 7-on-7 drills, while Foster played the first round of 11-on-11 action, and Brown then replaced him during the second such segment.

2. Doctson pain free: Second-year wide receiver Josh Doctson said he woke up one day last month and couldn’t remember the last time he felt soreness in his Achilles tendons. He said he just had to stop and offer a prayer of thanks because he didn’t even realize that he had taken the lack of pain for granted.

Doctson, determined to rebound from last year’s injury-plagued season, looked good Thursday. He displayed great footwork, particularly as he put a move on Bashaud Breeland at the line and ran free for a catch. Later, Doctson showed good speed as he raced by Quinton Dunbar on a deep throw up the left sideline. Doctson consistently created separation on his routes and made tough catches at times. He attributes the encouraging body of work to his decision to continue training in Ashburn after minicamp. Many players use that time to vacation, but Doctson said, “I just wanted this day. Circled it on my calendar.” It’s one day, but if Doctson can duplicate Thursday’s work, he’ll show why he was so highly regarded coming out of TCU last season.

Thursday was a good day as a whole for Washington’s top receivers. Terrelle Pryor and Jamison Crowder also ran good routes and created separation. Kirk Cousins said that, despite losing Pierre Garcon and DeSean Jackson to free agency, Washington’s offense will remain effective with additional fine-tuning.

3. Smith’s lessons from Williams: Outside linebacker Preston Smith looks bigger across the shoulders and chest and smaller around his midsection. He says he has lost roughly eight pounds after changing his diet (primarily avoiding fried foods in favor of baked). Smith said he hopes putting better stuff into his body produces better results on the field.

Smith, who managed just 4 1/2 sacks last season, faces quite a bit of pressure with Junior Galette coming back and Ryan Anderson being drafted in the second round. He needs to fight to hold on to his starting job. But every day is tough because he faces Trent Williams so often. Smith said he’ll attack the Pro Bowl tackle, and Williams will fend him off with one method on a string of plays, and just when Smith has figured out what’s coming, Williams switches it up and throws him off balance again.

Smith said to avoid getting frustrated, he reminds himself that it’s just practice. But he’s glad he doesn’t have to face Williams in games. Smith has room for improvement. He might take a quick first step, but his second and third steps often look slower, as if he’s trying to make up his mind what to do. But against a guy such as Williams, that split-second of indecisiveness makes a big difference.

Odds and ends

Injury report: Breeland didn’t finish practice because he was sick and held out as a precaution. Cornerback Lou Young suffered a groin pull, and Foster and offensive lineman Vinston Painter both suffered from cramps.

Ageless Davis: Entering his 12th training camp, 33-year-old Vernon Davis received treatment for hamstring and back soreness. But Davis didn’t miss any practice time. Davis truly loves being on the field. There’s a difference between soreness and injury, and Davis said this was something he could work through. Davis said that, despite his age, he still feels physically as he did when he was young. “Training camps are actually easier now than they were when I was younger. I just know my body and how to prepare now,” he said.

Shadowing Hood: After offseason practices concluded, Allen spent time training with nine-year veteran Hood. Those workouts have helped Allen get stronger and better learn how to push himself. For example, Allen would previously push 365 pounds on the sled, and he thought that’s about what he could do. Trying to keep up with Hood, he realized he hadn’t reached his limit. He’s now pushing 405 pounds on the sled. “He’s one of the hardest workers I’ve ever seen,” Allen said of Hood.

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