Of the four callups, Moya is the only one who hasn't been up yet this season. The top prospect in the Tigers' system according to MLB.com, Moya salvaged a difficult season at Triple-A Toledo by showing progress down the stretch. The big left-handed hitter batted .265 (39-for-147) from Aug. 1 on with 12 doubles, five home runs and 19 RBIs.
For the season, Moya batted .240 (120-for-500) at Toledo with 30 doubles, 20 homers, 74 RBIs, 27 walks and 162 strikeouts. He played almost exclusively right field for the Mud Hens until the final week, when he shifted over to left in a move that opens up the possibility of him competing for playing time there if the Tigers look internally this offseason to fill the corner spot opposite J.D. Martinez. For the next few weeks, he's likely to serve as a left-handed power bat off the bench while getting some starts in left.
"He'll get a handful of starts," manager Brad Ausmus said. "I wouldn't say he's going to be in there every day."
Marte filled in surprisingly well for an injured Miguel Cabrera in July and August, batting .250 (13-for-52) with four doubles, three home runs and seven RBIs. He batted .275 at Toledo with 25 doubles, 15 homers and 65 RBIs.
Krol has shuttled between Detroit and Toledo three times, mastering Triple-A hitters but struggling at times to attack opponents in the big leagues. He has allowed 16 earned runs on 30 hits over 21 1/3 innings, walking 13 and striking out 22 in the Majors.
The surprise is the 34-year-old Wilson, whose return restores infield depth lost when Jose Iglesias went on the DL. Wilson went 8-for-21 in Detroit earlier this year, and he batted .252 with three homers, 30 RBIs and 10 stolen bases for Toledo.
"We need another middle infielder," Ausmus said. "Iggy's not going to be able to play for a little bit. [It's important] to have the ability to replace a guy like [Ian] Kinsler in a lopsided game or even if Kinsler's not playing, like the other day, just pinch-hit him and get him out [of the game] rather than having to put him at second base, as much as he's played."
The move to designate Fields potentially ends a hometown-hero story for the son of longtime Tigers coach and instructor Bruce Fields. The Tigers signed him away from a commitment to the University of Michigan with a sixth-round pick in the 2009 Draft, then opened his pro career at Class A Advanced Lakeland.
Fields spent nearly three full seasons in Lakeland, then broke out for Double-A Erie in 2013. Injuries shortened his '14 campaign, but a solid Spring Training and breakthrough start for Triple-A Toledo earned him his first big league callup in June as a fill-in while Rajai Davis was on paternity leave.
Fields struggled down the stretch, batting just .206 (52-for-253) to finish with a .229 (103-for-450) average, 26 doubles, eight triples, seven home runs, 41 RBIs and 17 stolen bases. Add in Tyler Collins' emergence in Detroit, and Fields had traffic in front of him on the depth chart.
The news came hard to the family, Bruce Fields said, but it's part of the game.
"When one door closes, another opens," he said.
The Tigers have 10 days to either trade, release or outright the 24-year-old Fields. He'll have to clear waivers before Detroit can do the latter. The Tigers could conceivably add him back to the 40-man roster next month to protect him from the Rule 5 Draft. He's one year away from Minor League free agency.
Jason Beck is a reporter for MLB.com. Read Beck's Blog, follow him on Twitter @beckjason and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.