SAN DIEGO -- Jonathon Niese is on track to return to the Mets' starting rotation Monday against Seattle.
General manager Sandy Alderson said the lefthander is "still a go at the moment" after a bullpen session Friday at Petco Park. It was his second throwing session since landing on the disabled list with left shoulder inflammation and fatigue.
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Manager Terry Collins said Niese reported no issues after his bullpen session but stopped short of saying he will be ready by Monday.
Daisuke Matsuzaka was moved into the bullpen for Friday night's series opener, though Collins said he might be held out this weekend as insurance if Niese isn't ready to pitch.
The Mets have four players vying for playing time in leftfield, and it appears they will stay with the odd arrangement a while longer.
"You want to get them all in there,'' Collins said, "but they can't all be in there."
With Curtis Granderson entrenched in rightfield and Juan Lagares manning centerfield, the Mets must find time in left for Bobby Abreu, Eric Young Jr., Chris Young and Kirk Nieuwenhuis, who got the start Friday night.
The Mets have carried an extra outfielder at the expense of a true backup shortstop behind Ruben Tejada. They prefer the arrangement because it allows for an extra bat on the bench.
First-round draft choice Michael Conforto will make his professional debut on Saturday as the designated hitter with the Cyclones . . . The A's are celebrating the 25th anniversary of their 1989 World Series title with a reunion, but Alderson, the architect of that team, remained with the Mets.