Scheinblum, Bench, Rader, Rodriguez, Dal Canton and Schmelz—these are names to remember. They belong to players who have been infiltrating the major league scene en masse in recent days. The arrival of such newcomers is a traditional end-of-the-season ritual made possible by the expansion of big-league rosters from 25 players to 40 during the final month of play. Past experience indicates that a number of these youngsters will soon become regulars. Outfielder Richie Scheinblum of the Indians, Catcher John Bench of the Reds, as well as Pitchers Bruce Dal Canton of the Pirates and Al Schmelz of the Mets fit into the future plans of their parent clubs. And Doug Rader of the Astros and Aurelio Ituarte (Leo) Rodriguez of the Angels have already begun to establish themselves. Rader, 23 and tagged with the florid—and obvious—nickname of Red, has taken over as cleanup hitter, no small feat on a team with Jim Wynn and Rusty Staub. In his first 33 games, Rader, who plays first base and third, hit .336 and drove in 18 runs. Rodriguez (right), a mere lad of 19 from Sonora, Mexico, hit safely in nine of his first 10 games and fielded flawlessly at third base. He was signed by Angel Vice-President Marvin Milkes who, as a minor league executive, had the distinction of breaking in Ron Santo, Brooks Robinson and Zoilo Versalles. Says Milkes, "Leo is ahead of all of them al this stage." Dal Canton did not allow a run in 6? innings of relief last week and picked up a win against the Cardinals. Schmelz, though not as effective, did set a major league record in his very first game. He was the 25th in a long line of pitchers of sorts who have been employed by the Mets this season.