SANTA CLARA -- Four days before 49ers linebacker Kwon Alexander went down with a torn pectoral, Houston Texans star J.J. Watt sustained the same injury.

It was thought to be season-ending for both players. But Watt will return this week in the playoffs, and Alexander might not be far behind.

Alexander ended up getting Watt’s phone number from a former teammate, and the two players spoke as they were progressing through their respective rehabs.

“I talked to him,” Alexander said Thursday upon completing his first practice since his Oct. 31 injury. “I’m happy to see him back. I can’t wait to see him play on Saturday. He lifted me up a little bit. I appreciate him, too.

“You see he’s back and he’s been doing well.”

Watt returned to practice during the final week of the regular season. This week, the Texans activated him to their 53-man roster. Watt is expected to play Saturday when the AFC South-champion Texans open the wild-card round of the AFC playoffs with a home game against the Buffalo Bills.

Alexander, who went on injured reserve on Nov. 5 after surgery to repair his left pectoral, was designated to return off the injured reserve list on Thursday. The 49ers can activate him at any point. He took part in the 49ers’ hour-long practice on Thursday, lining up alongside starting middle linebacker Fred Warner during individual drills. Alexander wore a blue jersey to signify that he is off-limits for contact.

Kwon Alexander is back on the #49ers practice field. He’s wearing the blue no-contact jersey. pic.twitter.com/WjbeY0aI5v — Matt Maiocco (@MaioccoNBCS) January 2, 2020

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But it is uncertain whether Alexander will be in uniform for the 49ers’ first playoff game in the divisional round on Saturday, Jan. 11, at Levi’s Stadium. Alexander said he will be ready for whatever the team’s performance staff and 49ers coach Kyle Shanahan decide.

“Whatever coach tells me,” Alexander said. “I’m going to be ready for whatever situation it is. I’ll be prepared if it is.”