Saturday marked Darren Waller’s first practice at the team’s headquarters in Owings Mills. For a player who missed the entire 2017 season to serve a one-year suspension for violating the NFL’s policy on substance abuse, the tight end looked impressive at times, catching two touchdown passes in a one-on-one exercise in the red zone and making a couple of more catches in traffic.

But Harbaugh said Waller, 25, a converted wide receiver, has a long road ahead of him. He is returning from his second suspension in as many years and is fighting for a spot at a position that already includes incumbents Nick Boyle, Vince Mayle and Maxx Williams, 2018 draft picks Hayden Hurst and Mark Andrews, and undrafted rookie Nick Keizer.

“He needs to be here,” said Harbaugh, who was initially dismissive about Waller’s performance. “I haven’t seen the guy for a year. I love him, he’s a great guy, a talented guy and all that, but where’s he been? You’ve got to be here. You don’t just come waltzing in, and all of a sudden, you’re the starting tight end. You’ve got to prove it. You’ve got to do some things for us; you’ve got to make plays. I love him, but like I told him, I’m going to be the hardest guy on him of anybody. I’m going to be on him every single day because he’s got a lot to prove.”

Tight ends coach Greg Roman echoed that sentiment, saying: “He’s got a lot of work in front of him. He’s getting there, though. He’s really, really been cramming. He is cramming for the final exam right now, and [there’s] not a lot of sleep going on. He’s doing a very good job with it. He’s got some recall, being with us last spring. So that’s really been helpful. But he has to get into the grind with his teammates and get into football shape. He’s in good shape, but you don’t get into football shape without grinding through training camp. So he’s on his way.”

O. Brown’s body change: Many players experience weight loss in training camp as a result of practicing for two-plus hours in the heat and humidity. Orlando Brown Jr. is no different, but his body change seems to be for the better.

The rookie right tackle — who was the organization’s first of two picks in the third round of the NFL draft in April — is listed at 6 feet 8 and 345 pounds, but he said Saturday that he has lost some fat while adding muscle.

End zone: In addition to Waller, guards Maurquice Shakir and Randin Crecelius, strong safety Tony Jefferson and wide receiver Tim White returned to practice. Jefferson, who has been battling a hamstring pull, left Saturday’s session early. … The team practiced without outside linebacker Tyus Bowser, safety Bennett Jackson and tight end Maxx Williams. Wide receiver Quincy Adeboyejo (upper leg muscle), linebacker Bam Bradley (ACL) and cornerback Jaylen Hill (right ACL, MCL) remain on the physically unable-to-perform list. … Jimmy Smith was credited with only one tackle Thursday, but the fact that the cornerback was on the field after tearing his left Achilles tendon Dec. 3 was noteworthy.

edward.lee@baltsun.com

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