NAPA (AP) — Clive Walford wasn’t bothered that Oakland coach Jack Del Rio pulled him out of the final 20 minutes of his first practice in training camp out of concern the rookie tight end might get fatigued.

After missing the first nine days with an apparent leg injury, the Raiders’ third-round draft pick understood Del Rio’s reasoning Tuesday.

“Coach is still trying to hold me back a little but it felt great to be out there with my teammates,” Walford said. “I thought I was in shape to actually run with the team but I was a little behind in that category. As practice kept going on, I picked it up.”

Walford broke almost every tight end record at the University of Miami and is expected to play a significant role in offensive coordinator Bill Musgrave’s first season with the Raiders.

The team hasn’t disclosed the nature or extent of the injury, but the training staff was cautious with him during his rehab.

Back on the field Tuesday for an evening workout, the 6-foot-4-inch, 250-pound Walford went through several individual position drills, took part in a handful of team scrimmage plays and also spent time working on special teams.

Walford did not finish an agility drill, spoke briefly with Del Rio then returned to take part in a half-speed goal-line drill before watching the remainder of practice on the sidelines.

“I thought we got a good amount of work where I thought there might be fatigue involved with a couple of the guys because they have not been working like the other guys,” Del Rio said. “I went ahead and pulled the plug on that last period or so.”

Walford has a lot of ground to make up.

Mychal Rivera, who was second on the team with 58 receptions, 534 yards and four touchdowns in 2014, has taken the majority of reps with Oakland’s first-team offense while undrafted free agent Gabe Holmes has handled the backup duties.

Veteran Lee Smith, signed as a free agent in the offseason, has been unable to practice recently with an undisclosed injury.

While his workload was kept to a minimum in his camp debut, Walford still make an impact. During one play in the team scrimmage period, Walford lined up on the left side then pulled to the right and stood up defensive lineman C.J. Wilson with a solid block.

That’s an aspect of Walford’s game that tended to get overlooked at Miami, primarily because it was overshadowed by his pass-catching ability.

The Raiders drafted him because he could do both.

“When I was at Miami because people said I couldn’t block, so I tried to prove people wrong,” Walford said. “I take blocking very serious. If you’re in my way, I’m just trying to roll over you. I like to put in the dirty work. Then after all that had work, the receiving and all that will come.”

Del Rio hasn’t said whether Walford will play in Friday’s preseason opener against St. Louis.

“He’s a football player that had a really good spring and we look forward to getting our hands on him and getting him to work,” Del Rio said. “We’d like to avoid that yo-yo process where he’s back and forth. Hopefully we let (the injury) settle down and we can put it behind us.”

NOTES: Del Rio didn’t seem entirely pleased with part of the team’s first practice after returning from a day off. “It was OK,” Del Rio said. “I think we’ll do things a little better but there were some good things and some things need to be a lot better.” ... Wide receiver Rod Streater did not practice. Linebacker Sio Moore also sat out.