The tournament has been catching up after rain caused long delays both Thursday and Friday. The third round was suspended at 8:45 p.m. (ET) due to darkness.
The third round will resume at 8:15 a.m. Sunday morning. The final round is slated to begin at 9:25 a.m. with the players remaining in the same threesomes.
Jay Haas, Wayne Levi, Gil Morgan and Tom Watson are tied for third place at 4 under par through nine holes of their third round. John Harris also stands at minus-4, having completed eight holes. Harris and Levi shared second place entering the third round.
Irwin fired a 2-under 69 earlier Saturday to take the lead into the third round. He played the front nine second during that round and played those holes at 4-under 31.
However, in the third round Irwin parred each of the first nine holes he played at Valhalla Golf Club prior to play being called for the evening.
Irwin, therefore, played 27 holes on Saturday and will have to play another 27 on Sunday to complete the event.
The Canadian Barr tripped out of the gate with a bogey at the par-4 second. He erased that mistake with a birdie at the sixth and climbed into second place with birdies at the eighth and ninth.
Craig Stadler, who has won four events in his brief Champions Tour career, stands alone in eighth place at 3 under par through nine holes.
Fuzzy Zoeller, the 2002 Senior PGA Champion, is 2 under through 11 holes of his third round. He is at 2 under par for the tournament and shares ninth place with Walter Hall (10 holes) and Tom Jenkins (9).
Andy Bean, Mark McNulty and Dave Eichelberger are the final players in red figures at 1 under par. All three have completed at least 10 holes of the third round.
John Jacobs, the defending champion, is 2 over par for his third round. He stands at 7 over par through 12 holes and is tied for 47th.