San Diego traded defensive back Chuck Detwiler, defensive end…

The April 10, 1973 trade is supported by both draft-transaction records and Chargers historical material. Pro Sports Transactions records Buffalo sending its 1974 second-round choice to San Diego for Chuck Detwiler, Lee Thomas and a player to be named later. The choice became No. 43, used by the Chargers on Penn State offensive lineman Mark Markovich. A later Chargers media guide independently identifies the same Buffalo-derived second-round pick and ties it to the April 10 exchange. The legacy row duplicated the unidentified future consideration into multiple vague assets; the supported structure is three incoming Buffalo assets on the Bills side only if the player to be named later is eventually identified, not several separate unspecified placeholders.

San Diego received measurable roster value from the draft choice. Pro Football Reference and NFL career records show Markovich appearing in nine games for the Chargers as a rookie in 1974 and all 14 games in 1975. He did not start a regular-season game for San Diego, so this was depth rather than a high-end second-round hit, but 23 appearances still represent real value from the acquired pick. Markovich later played for Detroit, but those Lions seasons are not credited back to the Chargers' side of this trade.

Buffalo's named return did not translate into Bills regular-season production. Detwiler's 1973 NFL season was with St. Louis, where he appeared in 10 games and made six starts. Lee Thomas' 1973 season was with Cincinnati, where NFL records list him in nine games. That means neither named player in the April package appeared in a Buffalo regular-season game after the trade. The unresolved player to be named later prevents treating Buffalo's return as definitively zero, however, because the public record used here does not establish whether that later player reported, was waived, or created any subsequent value.

The Chargers therefore receive the better hindsight grade, but the unresolved third Buffalo asset keeps the margin moderate. A B- for San Diego reflects converting the pick into two seasons and 23 games of offensive-line depth. Buffalo receives a C- because the two identified players produced no Bills regular-season value, while the unidentified player to be named later cannot responsibly be assigned either zero or meaningful production without evidence. Confidence remains medium for that reason.