The Lightning's opening-day roster looks all but set.After closing out the exhibition season with a victory Saturday, Tampa Bay announced Sunday that it had trimmed its roster to 24, assigning defenseman Erik Cernak and forwards Alexander Volkov and Mitchell Stephens to AHL Syracuse.That left forwards Mathieu Joseph and Danick Martel on the roster, which must be at 23 before the season opener Saturday against the Panthers at Amalie Arena.Forward Ryan Callahan remains on the roster as well, but he is expected to miss at least the first month of the season as he returns from offseason shoulder surgery.It's not a surprise Joseph, 21, has stuck. After coming into camp on the roster bubble, Joseph scored four goals in the preseason — the latest of which came Saturday against the Panthers — and finished with eight points."He's definitely putting his best foot forward,'' coach Jon Cooper said last week. "His speed is his biggest asset. He has been using it. He's finding himself around the net and putting those goals home. So he definitely has made a positive impression on the coaching staff so far. You're looking for guys to step up, and he has continued to do it through this camp.''Martel, 23, was claimed off waivers from the Flyers early in training camp. He didn't put up the same numbers as Joseph this preseason, but the numbers he put up at AHL Lehigh Valley have the Lightning intrigued.Martel had 117 points in the AHL the past three seasons. Players who put up those types of numbers in their early 20s usually end up being able to play at the NHL level, Lightning GM Julien BriseBois said."(Martel) kind of fits our DNA in the sense that he is really fast, he's skilled and he is tenacious," BriseBois said after claiming him.Cernak, Volkov and Stephens put together strong camps, but the Lightning ultimately decided their time would better be spent with the Crunch to start the season. Cooper has said multiple times that it is better to get significant minutes in Syracuse than play seldom with Tampa Bay.This assignment gives the three time to develop and improve in the AHL, but don't be surprised to see any of them in Tampa at some point this season.