SANTA CLARA, Calif. — While San Francisco 49ers tight end George Kittle just opened his practice window this week and has a full 21 days to return from his hamstring injury before a decision must be made, he made his plans for Sunday night against the Atlanta Falcons clear on Thursday afternoon.

“I fully plan on playing on Sunday,” Kittle said. “As long as [coach] Kyle [Shanahan] lets me. It’s up to him. But hopefully I’m out there. Which I think I will be.”

The 49ers have been without their star tight end since early in the Sept. 7 season opener against the Seattle Seahawks. After 22 snaps, Kittle injured his right hamstring while running a deep route down the right sideline with 10:06 left in the second quarter.

Kittle, speaking to the media Thursday for the first time since the injury, said he knew something was wrong immediately and that the injury was actually a “full tear” of his hamstring.

“I just felt like a rubber band snapped in my hamstring,” Kittle said. “I was like, ‘Ah, I’ve just got to go to the locker room after that one.'”

According to Kittle, he got a bit lucky with where the tear in his hamstring was, as it did not completely tear away from the bone. Because of that, Kittle’s recovery time was significantly less than the three to six months it can take for a more severe tear to heal.

Still, Kittle has been not so patiently waiting to return to the field after missing the past five games as the Niners have managed to jump out to a 4-2 start. The five contests Kittle has missed are the second most he has missed in a season, trailing 2020, when he missed eight games because of knee and foot injuries.

Based on league rules that require players on injured reserve to miss at least four games, Kittle technically could have returned for last week’s game against the Tampa Bay Buccaneers. But Kittle said Thursday he wanted to be sure he wasn’t rushing back because he didn’t want to make the injury worse.

“I have been so very excited to play football since last season ended, and being only able to play 20-something snaps has been very difficult for me,” Kittle said. “I’ve been trying my best to get back as fast as I can without being an idiot and rushing it.”

Kittle was listed as a limited participant in practice Wednesday and Thursday, though he noted after Thursday’s session that he feels “really good” and “today felt better than yesterday.” A potential Kittle return has created plenty of excitement among his teammates, many of whom have said they feed off his enthusiasm in addition to how productive he is on the field.

“George is awesome,” quarterback Mac Jones said. “He’s just great energy in the huddle and he’s just George. … He’s not going to change whether it’s practice or game day, so you know what you’re going to get. I’m excited to see where he’s at.”

If the 49ers activate Kittle for Sunday against the Falcons, they will need to make a corresponding roster move. Linebacker Fred Warner is slated to go on injured reserve with a dislocated and fractured right ankle.

One other big question facing the Niners as Kittle works toward a return: Who will be throwing him the ball? Things seem to be trending toward Jones getting another start Sunday night as starter Brock Purdy continues recovering from a toe injury.

Purdy was again limited in Thursday’s practice, with Jones, who has been battling knee and oblique injuries, upgraded from a limited participant Wednesday to a full participant Thursday.

“[I] definitely felt like I need to practice regardless of how it felt,” Jones said. “Get the timing and everything down, so we feel good about it during the game.”

Jones wasn’t the only Niner trending positively on Thursday’s injury report. Defensive tackles Kalia Davis (hand), CJ West (thumb) and Kevin Givens (pectoral) were also bumped up from limited to full participation. Right guard Dominick Puni (knee) and receiver Skyy Moore (ankle) also returned to practice on a limited basis after missing Wednesday.

Wide receivers Ricky Pearsall (knee) and Marquez Valdes-Scantling (calf) did not participate, with Valdes-Scantling a new addition from Wednesday.