EDEN PRAIRIE, Minn. (AP) _ The Minnesota Vikings added a pair of cornerbacks Tuesday, signing Terrance Shaw and Ralph Brown.

The Vikings lost backup cornerback Ken Irvin before Sunday's opener against Dallas when he ruptured his right Achilles' tendon in pregame warmups. That left the team thin at cornerback behind starters Antoine Winfield and Brian Williams. Rhett Nelson and Rushen Jones, both second-year players, were the only backups.

Shaw has started 87 of the 125 games in which he has played. He spent the past two seasons for Oakland as a reserve cornerback. Shaw had 70 tackles in 15 games in 2003 before signing with Carolina in April. The Panthers cut him earlier this month.

Brown started 10 of 36 career games for the New York Giants and was cut by Washington this preseason.

``We think it's an upgrade in our depth,'' coach Mike Tice said.

The Vikings released cornerback Omare Lowe and practice squad safety Oliver Celestin.