The Yankees signed Mariners castoff Richie Sexson to back up Jason Giambi at first base and fill in at designated hitter. The 33-year-old was abysmal for Seattle in the first half this year, but his raw power is intriguing. Sexson will compete for playing time primarily with Wilson Betemit, who has received regular DH work in the absence of Hideki Matsui. Betemit was solid in May and June, but has slipped in July. Can Sexson take advantage of injuries to Matsui and Johnny Damon long enough to put together an useful, extended streak?