SEATTLE, Wash. — The Seahawks are involved in a low-scoring, defensive battle for the second straight week, playing to a 6-6 tie with the San Francisco 49ers at halftime. Here are a few notes from the first half of the Seahawks' Week 2 game:

• Seattle's defense was dominant early, forcing three punts to go along with a Bobby Wagner interception on San Francisco's first four possessions. The 49ers didn't gain a first down, other than by penalty, until midway through the second quarter on their third possession of the game. The 49ers did, however, gain 61 yards on a Carlos Hyde run, setting up a second-quarter field goal. Hyde also broke free for a 27-yard gain on San Francisco's final possession of the half to help set up another field goal.
• After going 3 for 12 on third down last week, the Seahawks converted their first two third downs Sunday, as well as a fourth-and-1 attempt, leading to an eventual Blair Walsh field goal to give Seattle an early 3-0 lead. The Seahawks finished the half 5 for 12 on third down, but two of the non-conversions came in the red zone, forcing Seattle to settle for short field goals.
• Blair Walsh is now 5 for 5 on field-goal attempts this season.

• After finishing with only one catch last week in his first game back from a broken leg, Tyler Lockett was very involved in the offense Sunday, hauling in 5 passes for 59 yards.
• Tight end Jimmy Graham briefly went down with what looked to be a leg injury, but was back for Seattle's next series.
• Cornerback/special teams standout Neiko Thrope left the game with a ankle injury. His return is doubtful.
• Bobby Wagner's first interception of 2017 came against the same opponent as his lone interception last year, with Wagner stepping in front of a Brian Hoyer pass to give the Seahawks a short field, which they would eventually turn into a field goal.

• Michael Bennett had a third-down sack to end a San Francisco drive, giving him 2.5 this season.
• Recently-acquired defensive tackle Sheldon Richardson combined with Kam Chancellor for a big stop on third-and-1 to end one San Francisco possession, and had a tackle for loss on another 49ers drive that ended in a punt.
• Michael Wilhoite made his Seahawks debut, playing strongside linebacker in place of an injured Terence Garvin.