Steelers add rookie CB to bolster banged-up secondary

With their secondary thinned by injuries, the Pittsburgh Steelers on Saturday signed rookie free agent cornerback Jovon Johnson, who had recently auditioned for team personnel officials and coaches.

The move was necessitated by injuries to two veteran cornerbacks, starter Deshea Townsend and top backup Ricardo Colclough.

The team's first-round choice in the 2004 draft, Colclough was placed on season-ending injured reserve last week with a neck injury he has told friends might be career-threatening. Townsend suffered a strained hamstring in Wednesday's practice and is listed as questionable for Sunday's game against the Kansas City Chiefs at Heinz Field. Although the injury showed improvement during the week, a decision on Townsend's availability probably won't be made until Sunday morning.

Pittsburgh created a roster spot for Johnson by releasing No. 3 quarterback Brian St. Pierre. A fourth-year veteran, St. Pierre played for the Steelers in 2003 and 2004 and with Baltimore in 2005, then was waived by the Ravens during the preseason. He re-signed with the Steelers the week of the season opener when Ben Roethlisberger underwent an appendectomy and Pittsburgh needed another quarterback.

Johnson, 22, is an Erie, Pa., native who played at Iowa State. He was signed by the New York Jets as an undrafted free agent in the spring, spent four weeks in their training camp, then was released. He recently signed to play with the Las Vegas Gladiators of the Arena Football League, but his Steelers contract will supersede that deal.

Although he lacks size (5-foot-8, 178 pounds), and did not run very quick 40-yards times for scouts in his predraft workouts (4.6-second range), Johnson is a natural ballhawk. At Iowa, he intercepted 17 passes, the second most in Hawkeyes history, and was also a solid performer on special teams.

There is a chance, if Townsend cannot play Sunday, that Johnson will dress for the game.

Len Pasquarelli is a senior NFL writer for ESPN.com. To check out Len's chat archive, click hereInsider.