Phelps uses 50m free to work on butterfly

Mesa, AZ ( - Michael Phelps concluded his first swimming meet since 2012 on Friday morning after swimming butterfly during the 50m freestyle prelims at the Arena Grand Prix.

Phelps touched the wall in 24.06 seconds and didn't qualifying for the 50m free final, which was won Friday night by Nathan Adrian in 21.73 seconds.

A night earlier, Phelps finished second to fellow American Ryan Lochte in the 100-meter butterfly final.

Phelps retired after winning six medals in London, saying he wanted to see more of the world than its hotels and swimming pools.

But the layoff lasted just 20 months before USA Swimming said last week Phelps would be in the Mesa field.

Three of Phelps' record 18 Olympic gold medals came in the 100 fly. He has a record 22 Olympic medals overall.