When LeSean McCoy went down with a knee injury in Week 15, it was Karlos Williams and Mike Gillislee -- two relatively unknown backs -- that stepped up in his absence. The picked up right where Shady left off and performed admirably, helping the Bills lock up the rushing title for Buffalo.

On Monday, the Bills rewarded Gillislee and a handful of others. The team announced that they have signed Gillislee, cornerback Mario Butler, wide receiver Greg Salas and punter Colton Schmidt to contract extensions.

EXTENSIONS SIGNED: CB Butler, RB Gillislee, WR Salas, P Schmidt Plus 7 to future contracts: https://t.co/dkPkj4Z6VH pic.twitter.com/WryRFH2f07

— Buffalo Bills (@buffalobills) January 4, 2016

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Schmidt had an outstanding season with the Bills, ranking seventh in the league in net punt average. Gillislee had ben averaging more than 10 yards per carry entering Week 17, but struggled in the finale and ended the year with a very respectable 5.7 yards per carry.

As for Butler and Salas, they both made impacts at separate times. Butler started one game and had five pass breakups to go along with 15 tackles. Salas had a helping hand in the Bills' win in Week 17, catching three passes for 41 yards.