Jerry Pate is one stroke behind the leaders at minus-6 after his second straight round of 68 at the TPC of Tampa Bay. Bruce Fleisher jumped into a tie for fifth at 5-under-par 137 thanks to a 67. He was joined there by Larry Nelson, who posted 69 Saturday.
Loren Roberts, who has won the first three events of the Champions Tour season, shot 69 for the second straight day and stands at 4-under-par 138. He was joined there by Scott Simpson (68), Des Smyth (70), Bobby Wadkins (70) and Gary McCord (71).
McNulty shared the lead entering the round and tumbled down the leaderboard early in his round. He started on the second nine and faltered to back-to-back bogeys from the 14th to slide to 4 under.
Around the turn, the five-time winner on the Champions Tour birdied the fifth and sixth to get back to even-par for his round. The Zimbabwean carded his last birdie on the eighth to close at 7 under.
'In general, I'm happy with a 70,' McNulty said. 'The wind is totally different here and I haven't played this course in the wind. I'm obviously pleased with my position and I know what needs to be done.'
James collected one birdie over his opening six holes. The Englishman then picked up consecutive birdies from the seventh to get to 4 under.
The 52-year-old wrapped birdies on the 10th and 12th around a bogey on 11. James birdied the 15th to get within one of the lead, then birdied 16 to gain a share of the top spot.
'I struck it pretty well today,' said James. 'It's only my second event and last week I was pretty pathetic, so it's a lot better. It was encouraging.'
Irwin, who owns a tour record 44 wins, birdied three of the first five holes to move to 5 under. However, he settled in with 11 straight pars.
The 60-year-old closed with a birdie on 17 and another at the last to finish at minus-7.
'I feel like I've left a few out there, but coming in with two birdies on the final two holes sort of eliminates some of that,' said Irwin.
Bruce Lietzke shared the first-round lead with McNulty, but struggled to a 3-over 74 to slide to 3-under-par 139. He was joined there by Brad Bryant, Leonard Thompson, David Eger, Morris Hatalsky and Tom Kite.