Denver Broncos' 2018 free agency: Tramaine Brock adds versatility to secondary

Keenum to Broncos is first QB domino to fall (1:31)

Adam Schefter discusses Case Keenum's early intention to sign with the Broncos and how Keenum's signing affects other teams in the quarterback market. (1:31)

A breakdown of the Denver Broncos' 2018 free-agent signings.

Tremaine Brock, CB

The Broncos added Brock, who played for Minnesota last season, on Wednesday. Here's a closer look:

Grade: C. Brock immediately offers versatility as a veteran who has played full-time as an outside cornerback and also predominantly played nickelback in other seasons.

What it means: It's a good start on trying to deal with life after Aqib Talib. Brock is a savvy veteran and at his best he's shown himself to be a sure tackler in the open field. He's had a five-interception season (2013), but there has been little middle ground with his play as he has either played well or struggled mightily. He's a quality special teams player, but on defense Brock is not of Talib's level on the outside and he isn't as proficient as Chris Harris Jr. in the slot, so it will interesting to see how they fit him into the defense.

What's the risk: Moving Talib in a trade was, in large part a financial move for a team that wanted some additional cap space. But even if the Broncos believed Talib, at 32, was poised for a decline, they still have work to do to cover his absence. Harris and Bradley Roby are the starters, but Brock will turn 30 in August and has started more than seven games in just two of his previous eight seasons. He figures to appear in plenty of the specialty packages if things go as the Broncos hope, but if the plan is for the top three cornerbacks to be Harris, Roby and Brock, that isn't as strong a lineup as they had with Talib. Brock has to be part of the solution, but more help will needed.

Case Keenum, QB

Grade: A-minus. Well, it’s an A- if Keenum is the guy who helped the Vikings to an 11-3 record in his 14 regular-season starts as they powered into the NFC Championship Game. It’s clear Broncos senior personnel advisor Gary Kubiak, who coached Keenum for two seasons with the Houston Texans, had some influence in this decision.

What it means: The Broncos moved quickly, as Keenum figures to be the first of the high-profile quarterbacks available in free agency to sign a contract when things officially open Wednesday. With a deal that will come in at a more economical level than what Kirk Cousins will get, it will give the Broncos a little more flexibility to make some other additions. They also can go the best-player-available route with the No. 5 pick of the draft and could end up with one of the two best players on the board -- Saquon Barkley or Bradley Chubb -- if the run on quarterbacks comes at the top of the first round.

What’s the risk: That Keenum doesn’t hold the form he showed last season, his sixth year in the NFL. The 2017 season marked the first time he started more than nine games, as well as the first time he topped 11 touchdown passes in a season. His 67.6 percent completion rate was by far his career best, and it was the first time he attempted more than 200 passes in a season. The Broncos have gone all-in on the idea Keenum is an ascending player with plenty of room to grow in their offense.