With Boston Celtics star Rajon Rondo sidelined with a hand injury, rookie Marcus Smart is filling in as the starting point guard.  A Rondo trade could be - at least partly - contingent on how Smart plays up until the February deadline.

Rondo likely won't be ready to play until a week or two into the regular season, which has coach Brad Stevens handing the starting reins to Smart.  The former Oklahoma State standout isn't expected to be a breakout star right out of the gate, but if he is, it could convince Celtics president Danny Ainge that the team can do without Rondo.

Judging from Smart's first preseason game against the Philadelphia 76ers on Monday, that won't happen.  Smart - again, he's not expected to be an instant All-Star - went 0 for 8 from the field while adding six assists, three steals and solid defense.

"...What Marcus does to affect the game is going to be hard to find on a stat sheet in a lot of games," Stevens said after the Celtics' 98-78 win, according to the Boston Globe.  "I mean he's so tough defensively and he's one of these guys that I think will get stronger as the game goes along defensively."

The latest signs indicate Rondo won't be traded.  Rondo and Ainge seemed to be on the same page when they spoke at media day last week, with Rondo saying he wants to stay in Boston and Ainge saying No. 9 was worth a max contract. 

If Ainge doesn't think Rondo will bolt as a free agent in July, and if Ainge doesn't want to do a complete top-to-bottom rebuild of the roster, then there's no reason for him to trade Rondo.

Sean Deveney of Sporting News reported on a recent episode of the "Celtics Beat" podcast that whether Ainge trades Rondo depends on two things: 1) how Rondo plays early in the season, and 2) whether Ainge can go all-out and trade for a big-name star before the February deadline.

If the Celtics aren't able to bring somebody in this season, Deveney said the situation with Rondo becomes trickier.  If Ainge doesn't trade Rondo and decides to give him a max deal, he'll first want to know that he can bring in a big name free agent beforehand.  Deveney named Memphis Grizzlies center Marc Gasol as one potential July target.