ENGLEWOOD, Colo. -- For many, free agency in the NFL -- or the part folks really seem to care about in the drive-time world -- is essentially those first 48 hours after the market officially opens.

That's when the biggest names sign the biggest contracts and then pose for the customary photos, new jerseys in hand, alongside the people who wrote the checks. But John Elway, the Denver Broncos' president of football operations/general manager, likes to remind those who listen that "free agency doesn't stop after that first weekend."

While the Broncos did dive early into free agency to make their biggest deal -- $36 million for two years to quarterback Case Keenum -- they still have work to do now that the first week is in the books.

Most notably they're still looking at offensive linemen, particularly those who can play right tackle, as well as wide receivers and defensive backs. But as the opening days of free agency have come and gone, the players who remain unsigned are often either a little older in NFL terms or have a question or two in tow.

So it becomes about short-term fit, about whether the player fills a specific role for a season or two at most.

"We'll continue to work in free agency, see how we can improve and see what is out there," Elway said last week. "We've got to do a great job of getting the right guys that can come in and help us.”

The Broncos also have 10 draft picks at the moment. If they use them all, it would be the team's largest draft class since 2009 when they also selected 10, including Knowshon Moreno and Robert Ayers in the first round.

The team added defensive lineman Clinton McDonald after free agency's initial swirl with a two-year deal earlier this week. With Derek Wolfe coming back from neck surgery and Adam Gotsis' future uncertain given his arrest earlier this month in connection with a rape accusation in an alleged incident that occurred when he was at Georgia Tech, McDonald is a player who should contribute immediately in the team's rotation.

McDonald has played 97 games in his career with 36 starts -- 34 came in his four seasons with the Tampa Bay Buccaneers.

But in the weeks ahead, an offensive tackle would be the most likely Broncos signing given many league personnel executives say this year's draft class is thin there overall, especially for teams who'd like a rookie to contribute immediately. Multiple personnel evaluators say that fact influenced the market around the league in free agency's first days; Nate Solder signed a $62 million deal with the New York Giants and Chris Hubbard signed a $36.5 million deal with the Cleveland Browns.

Players like 2014 Broncos draft pick Michael Schofield, former Broncos right tackle Donald Stephenson, Seantrel Henderson, Marshall Newhouse and Benjamin Ijalana also quickly signed one-year deals, which has significantly thinned the ranks of available tackles. There are still players like Austin Howard and Byron Bell available -- both could line up at right tackle. Howard is 30 and Bell is 29.

The wide receiver market also was depleted as Sammy Watkins, Allen Robinson and Paul Richardson quickly signed deals for at least potentially $40 million overall. Of the remaining unsigned receivers Jeremy Maclin and 2010 Broncos draft pick Eric Decker are among the most accomplished. Dez Bryant would be another accomplished option if he were to be released by the Dallas Cowboys.

As is the case later in free agency, there are questions. Maclin had a career-low 40 receptions last season in Baltimore, and Decker averaged a career-low 10.4 yards per catch in his one season with the Tennessee Titans.

"We have time," Broncos coach Vance Joseph said. "There are still guys out there who can help us and we'll give those players a look. But there is a lot of work to do over the next few months."