About 40 minutes into the San Francisco 49ers' first practice of training camp, the team's top selection in the 2017 NFL Draft, Solomon Thomas, was in an office overlooking the practice fields officially signing his four-year rookie contract. Thomas then raced downstairs to change into his practice jersey and shorts, grab his helmet, and trot onto the field to join his teammates.

He may have looked ready to jump into the action, but Thomas played the role of an observer for what remained of the team's practice. While he worked with strength and conditioning coach Ray Wright individually and went through his conditioning test, his Friday work remained very light.

On Saturday, Thomas is expected to be a full participant in the team's second practice session. That time cannot come soon enough for the rookie. On Friday, Thomas told the media that he wanted to be out on the practice field with his teammates, but he left the contract details in the hands of his agent.

Thomas was unable to join his new 49ers teammates during the team's offseason program. It had nothing to do with his contract but had everything to do with a league policy that prohibits a rookie player from joining his team until his school has completed finals. For Stanford, which is on the quarter system, that date fell just as the 49ers were completing their offseason program in mid-June.

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"I did miss OTA's because of my school and all that," Thomas said on Friday. "But I feel like, with all my training, I've been doing great and just putting extra work in on my own. During that time, I didn't take any time off. I was training, getting ready. I had the iPad. I was watching film so I feel like I'm right there with everyone. I'm just ready to get out there and get on the field tomorrow."

Thomas said that he has been in the area. On Thursday, he spent his day at Stanford just waiting to receive word from his agent. He spent the time working out at his former college and trying to kill time until he heard something.

"Both parties worked extremely hard and they got it done as quick as possible and I couldn't be happier that I'm here right now," Thomas said.

Thomas believes that the 49ers defensive line has a lot of depth and talent. "It's going to be fun," Thomas said. "It's going to be a pretty dangerous d-line so I'm excited to be a part of it."

Thomas was selected with the third overall selection in the 2017 NFL Draft. He saw his stock rise in 2016 when he had 61 tackles, 8.5 sacks, and was First-Team All PAC-12. That stock rose further following the Sun Bowl against North Carolina and his showing at the NFL Scouting Combine, where he ran a 4.69-second 40-yard dash. While the bulk of his playing time at Stanford was in the interior, Thomas believes he is versatile enough to play wherever the 49ers ask him to.

"I came in (to Stanford) thinking I was going to be an outside linebacker," Thomas said in April during an interview on KNBR. "Played defensive end so I trained all my high school offseason to be an outside linebacker. Came in as a defensive end, played defensive end. Sophomore year, played nose guard and defensive tackle. Went back out to defensive end and kind of like a wide-9, wide-5 position sometimes as well.