(CNN) -- Dealing with Merion is turning out to be tough enough. But Tiger Woods is also battling an injury at the U.S. Open in Pennsylvania.

Woods revealed that he hurt his left arm while winning The Players Championship last month, which would explain why he grimaced noticeably on several occasions in the first round.

The world's top-ranked golfer was back in action in the second round Friday and shot a level-par 70 to complete two rounds at three-over-par 143.

Asked to provide more details about injury, Woods didn't elaborate.

"Well, it is what it is," Woods said.

Woods is bidding to win his 15th major but first since 2008 at the U.S. Open at Torrey Pines.

Back then he had to deal with seemingly a more serious injury -- a broken leg. He memorably beat Rocco Mediate in a playoff.

Given the challenging conditions at Merion, Woods suggested his total might not be so bad heading into the final two rounds.

Storms caused delays of more than four hours Thursday -- Woods had to complete his first round Friday -- and play was eventually suspended due to darkness. Windy conditions added to the degree of difficulty at Merion's shorter East Course.

Woods, Rory McIlroy and Masters winner Adam Scott made for a dream pairing and while Scott struggled, Woods and McIlroy -- the second-ranked golfer -- fared better.

Seen chatting amicably during the round, the duo compiled identical scores in the first two rounds.

Beginning at the 11th hole, Woods birdied the 13th for a good start. Two bogeys, however, on the 14th and 18th, meant he had work to do on the first nine.

Answer the following questions:
1. Who is the highest ranked golfer?
2. During what championship did he injure himself?
3. What body part did he injure?
4. Which one?
5. What major is he attempting to win?
6. How many would that total in his career?
7. How long has it been since he has won one at Torrey Pines?
8. Was he injured then, too?
9. Which body part was injured back then?
10. When did storms cause delays?
11. What caused a delay on Friday?
12. On what holes did Woods score a bogey?
13. Which did he birdie?
1. Tiger Woods
2. The Players Championship
3. His arm
4. Left
5. U.S. Open
6. 15
7. Since 2008
8. Yes
9. Broken leg
10. Thursday
11. Darkness
12. 14th and 18th
13. 13th