With the Bears employing a 3-4 defense for the first time in franchise history in 2015, three outside linebackers were the unit's top playmakers.
After missing the last eight games with a torn ACL in his first year with the Bears in 2014, Houston rebounded in 2015 while switching from defensive end to outside linebacker.
He saw little playing time early in the season. But after Jared Allen was traded to the Panthers and McPhee suffered a knee injury, Houston took advantage of expanded reps. After playing only four snaps in a loss to the Vikings, he compiled 28 tackles, five sacks and six tackles-for-loss during a six-game stretch from Nov. 9-Dec. 13.
The hot streak began in a Monday night win over the Chargers when Houston sacked Philip Rivers on back-to-back snaps on San Diego's final drive to help ice a 22-19 victory.
Houston's seven sacks over the final nine weeks of the season were tied for sixth most in the NFL. He helped the Bears record 20 sacks in their last seven games, tied for seventh in the league.
Young followed a similar path, bouncing back from a torn Achilles' tendon in 2014 and switching from defensive end to outside linebacker. Young became the third player in Bears history with at least one sack in five straight games in Weeks 11-15, joining Brian Urlacher and Steve McMichael.
McPhee's production tailed off during the second half of the season when he was limited by a knee injury. But the free-agent acquisition proved to be everything and more than the Bears expected when he recorded five sacks, 42 tackles and seven tackles-for-loss in the first seven games of the season.
The Bears didn't get as many impact plays from their inside linebackers in 2015, though
A 2012 first-round draft pick, McClellin lined up at his third position in 2015 after playing defensive end and outside linebacker in his first three seasons with the Bears. Like Acho, McClellin is due to become an unrestricted free agent next month.