Detroit Tigers -- Have signed free-agent relief RHP Bill Campbell, 37, to a one-year contract. Campbell, with the St. Louis Cardinals last year, was 5-3, four saves and 3.50 ERA. Texas Rangers -- C Don Slaught agreed to terms on 3-year contract extending through 1988 season. Other terms were not disclosed. Slaught, 27, batted .280 with eight home runs and 35 RBI in 1985, his first season with Texas since being acquired from Kansas City. He missed 1 1/2 months with pulled hamstring. FOOTBALL

NFL Draft -- Because of the playoffs, seven teams changed first-round selection positions for April 29 draft. Only 27 teams will draft in the first round because Buffalo traded its rights to the Cleveland Browns, who took quarterback Bernie Kosar in a 1985 supplemental draft. Based on record, AFC Central champion Cleveland (8-8) will draft ahead of nonplayoff qualifiers Washington (10-6) and Denver (11-5). But because they were in the playoffs, the Browns drop to 16th, behind other 8-8 teams. Washington (17th) was only one of four 10-6 teams not to make playoffs. San Francisco lost to New York Giants in NFC's first round, so it will draft 18th, followed by Giants and Dallas, whose opponents had better record than Giants' opponents. Denver is 21st, then New York Jets, Los Angeles Rams, all 11-5. At 12-4, Miami and Los Angeles Raiders draft 24th and 25th. As AFC champion, New England (11-5) dropped to 26th. Chicago (15-1) remained 27th by winning Super Bowl. First through 15th remained unchanged: Tampa Bay; Atlanta; Houston; New Orleans; St. Louis; Indianapolis; Kansas City; Minnesota; Pittsburgh; Philadelphia; Cincinnati; Detroit; San Diego; Green Bay, Seattle.