MIAMI -- Defensive lineman Igor Olshansky and cornerback Nate Jones signed with the Dolphins, who terminated the contracts of running back Larry Johnson and tight end Dante Rosario.
Tuesday's acquisitions shore up a defense that struggled in the first two games of the season, both Miami losses.
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Olshansky has started 98 games in seven seasons, including 14 for Dallas last season, when he had 38 tackles and no sacks. The Cowboys cut him just before this season.
Jones played with the Dolphins in 2008 and 2009 and spent the 2010 season with the Denver Broncos, who released him in August. The eight-year veteran has 10 career starts.
Johnson, a two-time Pro Bowl running back who sat out most of last season, played only briefly in two weeks with the Dolphins.
Copyright 2011 by The Associated Press