Thurman worked out for eight NFL teams after he helped lead the Stampeders to the CFL championship in late November. But he chose to sign with the Bears due in large part to the persistence they demonstrated while courting him.

"They contacted me throughout the course of all the workouts," Thurman said. "When it came down to it, I had a pretty good relationship with [the Bears]. It was nice. They were aggressive with me the whole time. To have a team checking in on me throughout meant a lot to me."

Obee concedes that it isn't easy scouting the CFL because the rules are different than the NFL. The Canadian game is played with three downs instead of four, 12 players on each side of the ball rather than 11, and a wider and longer field that sports two 50-yard lines, a center 55-yard line and end zones that are 20 yards long.

"It is a little bit of a projection," Obee said. "The main thing you look for are guys who dominate the competition and then you're looking for guys that show fundamental traits, instincts, competitiveness and physical tools. We also have age and size parameters.

"It's not apples-to-apples, so you're looking for things that translate and you're looking for guys who are really productive and just dominate their level."

Former NFL quarterbacks Warren Moon, Joe Theismann and Jeff Garcia all started their pro careers in the CFL, as did defensive end Cameron Wake, who has been voted to five Pro Bowls while spending the past 10 seasons with the Miami Dolphins.

Ex-quarterback Erik Kramer, guard Noah Jackson, defensive linemen Tyrone Keys, linebacker Jerrell Freeman and receiver Dontrelle Inman all played in the CFL before joining the Bears.

The Bears are hopeful that the three players they signed will earn roster spots. Williams-Lambert is a 6-3, 228-pound receiver who is similar in playing style to Bears 2018 seventh-round draft pick Javon Wims.

With the Roughriders in 2018, Williams-Lambert was named the CFL West Division's most outstanding rookie after catching 62 passes for 764 yards and four touchdowns. The Ball State product spent the 2016 season in the NFL on the Saints practice squad.

"He's probably more of a possession-type guy," Obee said. "But with that said, he's long, he's a good athlete, he's agile, and he's got really strong hands and good ball skills."

An undrafted free agent, Williams-Lambert was waived by the Saints in August 2017 after he sustained a shoulder injury in training camp a few days before the start of the preseason.

Asked about joining the Bears, Williams-Lambert said: "It's just a blessing. I didn't like how I went out with the Saints. I got a little taste of the practice squad, but I was hungry for more."

A Chicago native who attended Proviso West and Indiana State, Thurman appeared in 35 games with Calgary the past two seasons, recording 134 tackles, three sacks, three interceptions, three forced fumbles and 29 special-teams tackles.

"He's a really fast physical run-and-hit guy," Obee said. "At linebacker, we've transitioned the last several years to fast, more athletic guys and this guy fits that mold. He's not a true in-the-box, stack-and-shed guy. But he's a new-age-type of linebacker who can play in space and cover ground, and I think he'll be a good special-teams player too."

Thurman, who was born in Chicago and raised in Indianapolis, is excited about signing with the Bears after spending two seasons honing his game in the CFL.

"It means a lot; it means everything," he said. "I've been working towards my goal of becoming a professional football player in the NFL my entire life; I just took a different path to get there. But I'm glad to be part of an organization and I'm going to take advantage of this opportunity."

A Stanford product who grew up in Georgia, Vaughters played in 33 games with Calgary in 2017-18, registering 50 tackles, 11 sacks and eight special-teams tackles. His playing style compares to Bears outside linebacker Isaiah Irving.

"[Vaughters] can do a little bit of everything," Obee said. "He can pass rush, he can set the edge and he's athletic enough to drop and play in space. We see a versatile guy with good speed, good strength and good toughness. He fits with what we want an outside linebacker to be able to do."

Vaughters, who was born in Chicago but grew up in Georgia, originally entered the NFL in 2015 with the Packers as an undrafted free agent. He began his rookie season on Green Bay's practice squad but was waived after sustaining an injury in October. He has since spent time with the Patriots and Chargers but has yet to play in an NFL regular-season game.

Asked about signing with the Bears, Vaughters said: "It means a lot. It's been something I've been working toward since 2015 when I got an injury in my rookie year. What I've been working towards every day is to get the opportunity to make an NFL team again."

The three players the Bears signed from the CFL all have one important thing in common.

"The kids have a chip on their shoulder," Obee said. "They want to prove to people that they belong. I think that's also part of what can help them succeed. These guys are all driven to make it at this level."

While Obee monitors the CFL, Pace has other pro scouts who keep tabs on arena football leagues and college basketball players who possess NFL traits.