Just a little over a month after winning Super Bowl 50, the Denver Broncos are looking to fill the most important position in all of sports. With Peyton Manning’s retirement and Brock Osweiler’s decision to sign with the Houston Texans as a free agent, the defending champs don’t have a starting quarterback for the 2016 NFL season.

The Broncos were interested in keeping Osweiler, but not at the $72 million price tag that Houston offered. Trevor Siemian, a seventh-round pick out of Northwestern in last year’s draft, is the only signal caller on Denver’s roster, and the Broncos will be looking for a more experienced player to lead their title defense. There aren’t any great quarterbacks available in free agency, but Denver does have a few options.

According to Jason La Canfora of CBSSports.com, the Broncos have interest in Colin Kaepernick. The quarterback is still a member of the San Francisco 49ers, but he reportedly wants to be traded, and there’s speculation that the team will release him before his 2016 salary of $11.9 million becomes guaranteed on April 1.

However, there’s no guarantee that Kaepernick will become available, since general manager Trent Baalke has stated publicly that the team won’t be getting rid of the quarterback anytime soon. If the only way for the Broncos to acquire Kaepernick is through a trade, they might not be willing to meet San Francisco’s asking price, especially for a quarterback that is recovering from three surgeries.

It was just three years ago that Kaepernick led the 49ers to the Super Bowl, and he was considered to be one of the league’s best young quarterbacks when San Francisco fell short in the NFC Championship Game in the following season. But after he had a subpar 2014 season and posted just a 78.5 passer rating in nine games last year, Kaepernick was benched in favor of Blaine Gabbert.

In addition to trading for Kaepernick, the Broncos have reportedly had internal discussions about acquiring Mike Glennon from the Tampa Bay Buccaneers. Glennon had a productive 2013 season as a rookie with 19 touchdowns and nine interceptions, but he was benched for good after just six starts in 2014. The team drafted Jameis Winston first overall in last year’s draft, making Glennon expendable.

If the Broncos don’t make a trade, two free agents stand out as potential candidates to replace Manning and Osweiler in Denver. Both Robert Griffin III and Ryan Fitzpatrick are looking for new contracts.

Griffin was recently released after spending the first four years of his career with the Washington Redskins. His career has been very similar to Kaepernick’s, putting up strong numbers in his first season as a starter while leading his team to the playoffs, but eventually getting benched because of struggles and injury concerns.

Kirk Cousins started every game for Washington in 2015, and Griffin hasn’t thrown a pass since 2014 when he posted an 86.9 passer rating in nine games. According to ESPN’s Adam Schefter, Griffin is on Denver’s “list,” and the quarterback could soon have a visit with the Broncos.

Denver could go after Fitzpatrick, who had the best 2015 season of any available quarterback. He helped the New York Jets win 10 games, throwing for 31 touchdowns and 15 interceptions. Fitzpatrick and New York couldn’t agree on a new contract, though the Jets are still in play to re-sign him.

Last season was the best year of Fitzpatrick’s career, and he isn’t likely to reproduce those numbers as he enters his 12th NFL season. But the Broncos proved last season that they don’t need a top quarterback in order to be successful. Manning and Osweiler were mediocre at best during the regular season, and Manning played poorly in Denver’s Super Bowl victory.

The Broncos won a title on the strength of the best defense in football. While they’ve lost key players in free agency, the likes of Von Miller, DeMarcus Ware and Chris Harris will return, likely giving them a top defense for 2016.