Lopez, 30, made his major league debut in 2003 with the Toronto Blue Jays. He saw action in 72 games, going 1-3 with a 3.42 ERA and notched 14 saves.
Originally signed as a nondrafted free agent by the Seattle Mariners, Lopez was selected by Toronto in the Rule 5 draft in December of 2002.
He has a 2-5 record over his major league career with a 3.72 ERA in 111.1 innings, striking out 99 and walking 54. He is 34-26 in minor league action with a 3.25 ERA over 526 innings with 561 K's and 149 walks.
Matt Thayer split time between the Arizona Rookie League, Midwest League and California League in 2005. He hit .375 in three games with the Peoria Padres, .353 in 37 games with the Fort Wayne Wizards and .293 in 23 games for the Lake Elsinore Storm. Thayer, 24, is a career .314 hitter since being selected in the 31st round of the 2004 draft.
The Padres signed Trey Johnston after he was released by the Cubs. He split time between third base and catcher but has been practicing solely at catcher this spring. Johnston, 20, hit .262 in 37 games for Peoria in 2004 and hi .302 with the Peoria squad this pat season.
David Jay contributed to this report