The Dallas Cowboys will begin the season without one of the foundations of their offensive line after Tyler Smith was ruled out for between four and six weeks with a thumb injury.

Smith is scheduled to undergo surgery today (Tuesday) and will be placed on injured reserve with a designation to return. The move rules the three-time Pro Bowl left guard out of Sunday night’s opener against the New York Giants and at least three further games.

Head coach Brian Schottenheimer revealed that Smith had been dealing with ligament damage in his left thumb during training camp. The 25-year-old continued practising into last week in the hope of avoiding an operation, but the injury eventually prevented him from performing at his usual level.

“At the end of the day, you always see if you can kind of play through these things,” Schottenheimer said. “He’s done things like that, like a lot of guys have, [where] they’ve been able to play through them. Unfortunately, when you’re an offensive lineman, grip strength and things like that are really important. Again, we know he’s a quick healer, and we want to get it fixed. He’ll be back before too long.”

The timing leaves Dallas without its most decorated offensive lineman as a rebuilt unit prepares for an immediate examination against the Giants’ defensive front, while Washington, Baltimore and Houston follow during the mandatory four-game period Smith must spend on injured reserve.

The Cowboys have confirmed that T.J. Bass will replace Smith at left guard against the Giants. The former undrafted free agent has made 10 starts during three seasons with Dallas, including five last year, and was retained on a one-year, $5.8m restricted free-agent tender during the offseason. He also received regular first-team work while the Cowboys managed Smith’s workload during training camp. He allowed eight pressures and no sacks across 198 pass-blocking snaps in 2025, according to Next Gen Stats, giving Dallas greater confidence in its replacement than might ordinarily be expected behind an All-Pro-calibre starter.

“Tyler Smith’s a great player, but we feel really confident in T.J., and he’s put great film on here,” Schottenheimer said. “We tendered him the way we tendered him because we trust this guy as a football player. He’s a damn good football player that unfortunately is just playing behind a lot of really, really good players. So we have great confidence in T.J.”

Bass nevertheless inherits an important role within a line that was already carrying some uncertainty into the season. Tyler Guyton and Nate Thomas competed at left tackle during the summer, while former Pittsburgh first-round pick Broderick Jones arrived in a late-August trade to challenge established right tackle Terence Steele. Smith had represented a reassuring constant between those moving parts, the 24th overall selection in the 2022 draft having started at left tackle as a rookie after Tyron Smith was injured, then developed into one of the NFL’s leading guards after moving inside.

He has been selected for the Pro Bowl in each of his three seasons at left guard and earned second-team All-Pro recognition in 2023. Dallas secured him through 2030 last year with a four-year extension worth up to $96m, including more than $81m guaranteed, and Smith has proven durable despite dealing with several physical problems. He has missed only five games during his four-year career and played at least 16 times in three of those seasons, although he underwent surgery on his right knee in February.

The earliest he can return is Dallas’s Week 5 Thursday night meeting with Tampa Bay but, with that game arriving on a short week, the Cowboys may instead target their visit to Green Bay on 18th October if Smith requires the full six-week recovery period.