David Dupree/Getty Images

PITTSFORD, N.Y. (AP) -- Kevin Kolb injured his left knee Saturday when he slipped on a wet rubber mat while running between fields at Bills training camp.

Buffalo Bills coach Doug Marrone says the injury is not serious and expects the quarterback to return to practice - and his competition with E.J. Manuel for the starting job - within days.

Kolb was hurt while going from one field to another with his offensive teammates. As he ran, Kolb slipped on a wet rubber mat and stumbled awkwardly at the Bills training camp facility in suburban Rochester on Saturday.

Though Kolb did not fall, he had trouble standing and put his arm around the shoulder of head trainer Bud Carpenter. Kolb then tossed down his helmet in frustration, before sitting down on the field.

Carpenter briefly examined Kolb's knee before escorting him to the locker room. Workers then began sweeping water off the mats, which were in a tunnel between fields. The mats provided little traction, especially for players wearing cleats.

Kolb is entering his seventh NFL season after signing a two-year contract with Buffalo in free agency in April. Kolb was counting on kick starting his career in Buffalo after injuries contributed to him losing the starting job in both Philadelphia and the past two seasons in Arizona.

Copyright 2014 Associated Press. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.

SI Apps
We've Got Apps Too
Get expert analysis, unrivaled access, and the award-winning storytelling only SI can provide - from Peter King, Tom Verducci, Lee Jenkins, Seth Davis, and more - delivered straight to you, along with up-to-the-minute news and live scores.