by David P. Greisman

UPDATE: "Lee Purdy couldn't shift the final [half a pound]," promoter Eddie Hearn wrote on Twitter. "Fight goes ahead with Alexander. If Lee wins, he will fight for [the] vacant title next."

Caesars Atlantic City Hotel and Casino — Junior welterweight titleholders Lamont Peterson and Lucas Matthysse both made weight for their main event Saturday night at Boardwalk Hall in Atlantic City, with Peterson weighing in at the agreed-upon catch-weight of 141 pounds on the nose, while Matthysse was 140 pounds.

Peterson, 29, of Washington, D.C., is 31-1-1 with 16 knockouts. Matthysse, a 30-year-old from Argentina, is 33-2 with 31 knockouts and 1 no contest.

Devon Alexander came in at 146.7 pounds for his welterweight title defense against Lee Purdy, who tipped the scales at 148 pounds. Purdy had until 5:43 p.m. Eastern Time to drop that extra pound.

Alexander, 26, of St. Louis, is 24-1 with 13 KOs. Purdy, 25, of Colchester, Essex in the United Kingdom, is 20-3-1 with 13 KOs.

As for the undercard bouts:

- Shawn Porter weighed in at 150 pounds for his bout against fellow undefeated fighter Phil Lo Greco, who also came in at 150.

Porter, 25, of Akron, Ohio, is 20-0-1 with 14 KOs. Lo Greco, 28, of Toronto, is 25-0 with 14 KOs.

- Light heavyweight prospect Thomas Williams Jr. came in at 175 pounds, as did his opponent, Otis Griffin.

Williams, 25, of Fort Washington, Md., is 13-0 with 10 KOs. Griffin, 35, of Sacramento, Calif., is 24-12-2 with 10 KOs.

- Anthony Peterson, younger brother to Lamont, weighed in at 136.5 pounds for his bout with Dominic Salcido, who also weighed in at 136.5.

Peterson, 28, of Washington, D.C., is 31-1 with 20 KOs and is fighting for the first time since December 2011. Salcido, 29, of Rialto, Calif., is 18-4 with 9 KOs.

- British Olympic bronze medalist Anthony Ogogo came in at 159 pounds for his second pro fight, as did his opponent, Edgar Perez.

Ogogo, 24, of Lowestoft, Suffolk, is 1-0 with 1 KO. Perez, 34, of Puerto Rico, is 5-4 with 3 KOs.

- Haroon Khan, younger brother of former 140-pound titleholder Amir Khan, weighed in at 116.5 pounds for his second pro fight. His opponent, Vincente Medellin, was 115 pounds.

Khan, of Bolton, England, is 1-0 with no knockouts. Medellin, 25, of Riverside, Calif., is 0-5, also with no knockouts, of course.

- American Olympian Rau’shee Warren came in at 118 pounds for his fourth pro fight, while his opponent, Angel Carvajal, came in at 116.

Warren, 26, of Cincinnati, is 3-0 with 1 knockout. Carvajal, 29, of Chicago, is 2-1 with zero knockouts.

- Lightweight prospect Robert Easter weighed 133.5 pounds, while Eduardo Guillen weighed 132 pounds.

Easter, of Toledo, is 3-0 with 3 KOs. Guillen, of Brownsville Texas, is 0-2.

- American Olympian Jamel Herring came in at 134 pounds for his third pro fight. His opponent, Victor Galindo, came in at 134.5 pounds.

Herring, 27, of Coram, N.Y., is 2-0 with 1 knockout. Galindo, who hails from San Juan, Puerto Rico, is 1-1 with 1 knockout.

- Cesar Seda came in at 117.5 pounds for his bantamweight bout., as did his opponent, Miguel Tamayo.

Seda, a 27-year-old from Puerto Rico, is 24-1 with 17 KOs. Tamayo, who hails from Sonora in Mexico, is 14-5-2 with 12 KOs.

David P. Greisman is a member of the Boxing Writers Association of America. Follow David on Twitter @fightingwords2 or send questions/comments via email at fightingwords1@gmail.com