The Denver Broncos' entire starting defensive line from last season is entering free agency in one form or another. Three are poised to be unrestricted — Derek Wolfe, Shelby Harris, and Adam Gotsis — while the other will be a restricted free agent — Mike Purcell.

That exodus upfront creates a massive need for the team. Now, the Broncos will likely make overtures to get at least one of their own unrestricted free agents re-signed, and are sure to tender Purcell.

That means this team is likely to be a player in the free-agent market when it opens on March 18. The big-named guys, like Kansas City's Chris Jones and San Francisco's Arik Armstead, are attractive but will come with a max contract the Broncos would have to be willing to lay out.

Or, the team could look to the secondary free-agent market to plug some holes in the defensive trenches. One such candidate is former Baltimore Ravens' standout Michael Pierce.

Pro Football Focus ranked Pierce as their No. 42 free agent and predicts that he'll ultimately land with Vic Fangio in Denver. Here's what PFF had to say:

42. DL MICHAEL PIERCE – DENVER BRONCOS

Michael Pierce had a down year in his pivotal contract year. After posting PFF grades of 79.7, 86.9 and 91.0 in his first three seasons, Pierce lowered that mark to 69.1 in 2019. The Broncos might be able to get a bargain for Pierce if he’s able to get back to form, and they can play him in a near-identical role to what Shelby Harris played.

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A three-year, $15 million deal might seem a little steep for a trenchman who mostly specializes as a run-stuffer but that's the going rate for a starting-caliber player at the position. Although he doesn't offer much as an interior pass rusher, Pierce is stout against the run.

A former undrafted free agent out of Stanford (2016), Pierce has spent the last four years in Baltimore. He's been an off-and-on starter for the Ravens, up until this past season where he started a career-high 14 games.

Pierce only has 3.5 career sacks in 60 career games, but he can clog the middle and allow the off-ball linebackers in the scheme to swarm and tackle the ball-carrier. There is value to a 27-year-old player who can stand up blockers and occasionally penetrate the backfield.

And the truth is, the Broncos are woefully short on D-line talent under contract for 2020 with bonafide starting experience. Pierce would check a lot of the boxes, but ideally, the Broncos would want someone more like Wolfe, who can stuff the run and get after the QB, to start at one of the defensive end slots.

Keep an eye on Pittburgh's Javon Hargrave and Buffalo's Jordan Phillips as two under-the-radar free-agent options the Broncos could pursue in the second wave to bolster the D-line. GM John Elway has had success in years past finding value signings along the D-line who go on to make a larger impact, like Terrance Knighton and Domata Peko.

Follow Chad on Twitter @ChadNJensen and @MileHighHuddle.