Welcome back to The Rotation! Here are five topics in the world of Major League Baseball worth bantering about this week.

1. Who's the No. 1 No. 2?

Mere minutes after Derek Jeter was honored Sunday night, Astros third baseman Alex Bregman, wearing Jeter's number on his back, hit a grand slam off Masahiro Tanaka on the way to a 10-7 Astros victory in the second game of a day-night doubleheader in the Bronx.

So the Yankees retired No. 2 but couldn't retire No. 2.

As Bregman showed, the number might be buttoned-up in the Bronx, but it lives on elsewhere, in many cases -- like Bregman's -- as an homage to the Yankee great. Here, just for fun, is a power ranking of players currently donning the deuce:

  1. J.J. Hardy, SS, Orioles: Respected veteran off to a brutal start (.203/.240/.276 slash line).
  1. Denard Span, CF, Giants: 93 OPS+ and 98 wRC+ in 160 games with the Giants. Not the impact they expected.
  1. Andrelton Simmons, SS, Angels: Still basically all-glove, no-bat, but a marked increase in selectivity dating back to the middle of 2016 could reap rewards.
  1. Alcides Escobar, SS, Royals: Batting him in the leadoff spot is, like, the dumbest thing in baseball that consistently works. Ned Yost went back to that well last week, and the lowly Royals have gone 6-1 since!
  1. Brian Dozier, 2B, Twins: "Only" five homers through 30 games, but last year at this time he only had four and went on to hit 42.
  1. Khris Davis, OF, A's: Has come back down to earth after a 10-homer, 1.032-OPS April, but the little guy's got good power.
  1. Bregman, 3B, Astros: Still making adjustments at the plate but one of those guys you wish you could buy stock in.
  1. Jean Segura, SS, Mariners: Not a whole lot going as planned for the M's this season, but Segura (.371/.407/.517) has come as advertised despite an early hammy injury.
  1. Xander Bogaerts, SS, Red Sox: Maybe his career hasn't been the offensive explosion some imagined, but he's got a 128 wRC+ mark this season and is 19-for-51 with six doubles and a triple in May.
  1. Zack Cozart, SS, Reds: Has come down with Joey Votto Syndrome (that's a good thing). His walk rate has more than doubled, and his .432 OBP is the stunning part of his .995 OPS.

Not ranked: Troy Tulowitzki (on DL with hamstring injury), Adam Eaton (torn ACL), Tommy La Stella, Nick Franklin, Shane Peterson, Alexi Amarista, Luis Sardinas and Jeff Mathis.

2. "Hang"-ing around

The defending champion Cubs enter the week at 18-19, fourth place in the National League Central and 3 1/2 games back of the Cardinals, who took a series from them at Busch over the weekend. The Indians are in a little better shape after an HGTV-style renovation of their lineup Sunday led to an 8-3 win over the first-place(!) Twins, but at 19-17, they are hardly running away with the AL Central.

So the World Series hangover narrative lives. For the Cubs, Jon Lester, Jake Arrieta, Kyle Hendricks and John Lackey have all seen declines in their average fastball velocity, with the rotation's overall average velocity, as recorded by Statcast™, dropping from 91.4 mph to 89.2. For the Indians, Corey Kluber landed on the DL earlier this month with a back issue that had been bothering him all of April after pitching more than 250 innings last year, and Josh Tomlin and Trevor Bauer also had inflated April ERAs after career-high workloads.

But what's really striking about the sluggish starts of Chicago and Cleveland after an epic autumn are the areas that aren't even attributable to the Series.

If you assumed that the loss of Dexter Fowler's bat would be offset by the full-season return of Kyle Schwarber, well, Schwarber's early rust (.179/.313/.343) suggests otherwise, and it was already assumed that he'd be a defensive liability in the outfield. What's also surprising, beyond Schwarber's slow start at the plate, is that Albert Almora has graded out as average, at best, in center-field defense. The Cubs' outfield led the Majors in defensive runs saved by a wide margin last season. This year, it currently ranks 24th, and that defensive downgrade has contributed to their opponents' batting average on balls in play rising from .255 in '16 to .295 in '17.

Meanwhile, the Indians' supposed lineup boost from the Edwin Encarnacion signing simply hasn't arrived yet. Even amid Sunday's sudden offensive surge, Encarnacion was silent -- 0-for-4 with two K's. He has an uncharacteristic .206/.353/.341 slash a year after posting .263/.357/.529 marks, but even more uncharacteristic is his 28.9-percent strikeout rate -- 12 percent higher than his career average. His struggles contributed to the lineup's early susceptibility to left-handed pitching.

For what it's worth, FanGraphs still gives the Tribe an 85-percent chance of winning the AL Central (down from 87.5 on Opening Day) and the Cubs a 68.5 percent chance of winning the NL (down from 83.1).

"All you have to do is make the playoffs," Tribe shortstop Francisco Lindor said. "Then anything can happen. Just make it."

3. Ervin magic

The two years and $27 million remaining on Ervin Santana's contract were there for the taking last August. Any team could have claimed him, but nobody bit.

Perhaps they should have.

Santana won't maintain his current 1.50 ERA all year, but don't dismiss his early success as the product of a small and unsustainable sample. Go all the way back to last June 19, and Santana has a 2.12 ERA -- the second-best mark in the game among those with at least 15 starts from that point, trailing only Hendricks' 2.02 and just ahead of Clayton Kershaw's 2.23. Santana said he's annoyed that he's "walking a lot of guys" (a career-high 10.1 percent), but he's induced the third-highest percentage of poor contact this season.

"I don't think it's a flash in the pan," Twins chief baseball officer, Derek Falvey, said. "He's done a really good job of working with the catcher, but also as he's matured. Guys reconfigure how they use their pitches."

Maybe the Twins continue to ride Santana to unexpected contention. But if not, he could be a major trade chip for them. And this time, there would probably be takers.

4. Deal or no deal?

Speaking of the developing -- and possibly very deep -- starting pitching trade market, the D-backs' new-look front office, led by Mike Hazen, has a potentially interesting decision on its hands involving Zack Greinke.

Greinke has set off some alarm bells with his diminished velocity after late-season shoulder issues in 2016, but it's hard to argue with the results. Through eight starts, Greinke has a 2.79 ERA and 1.03 WHIP in 51 2/3 innings. He took a no-hitter into the eighth in his last start against the Pirates, and, despite the velocity dip, he's getting more swinging strikes than ever before (13.5 percent).

This could be an opportunity for Hazen, who inherited the Greinke contract that eats up 36.5 percent of the 2017 payroll and will pay him another $138.5 million from 2018-2021, to move some money. Maybe the D-backs wouldn't get much in the way of prospect help, but if a contending club were willing to absorb the highest average annual value in the game, the financial relief would be monumental for the D-backs, who really can't afford to have so much salary tied up in a mid-30s arm.

Here's the problem: The D-backs are decent. Sure, it's too soon to tell if they're decentness is an early season blip or a verifiable bounceback, but the way they rack up runs at Chase Field, the way their rotation has (thanks in no small part to Greinke) evolved into a more trustworthy group than it was a year ago and the way they've leveraged Archie Bradley in the bullpen all leads you to believe they could at least hang around in the Wild Card race.

If Greinke and the D-backs both remain relevant, it's going to be fascinating to see how the trade market develops. The D-backs might feel compelled to compromise their present for the sake of their future.

5. "We're going streaking!"

Have you heard about this guy who is abnormally close to winning MLB.com's "Beat the Streak"?

The fantasy game, in which users establish a virtual "hitting streak" by picking a different player each day that they think will get a hit, has been in existence since 2001. And in that time, not one person has had a streak last as long as that of 32-year-old Robert Mosley, who is just six successful picks shy of "breaking" Joe DiMaggio's record 56-game hitting streak and winning the $5.6 million prize.

Mosley has done this with a flair for the dramatic. He doubled down on Saturday, choosing both Ryan Zimmerman and teammate Bryce Harper with the chance to go from 49 to 51. Zimmerman singled in the second inning against the Phillies, and Harper's only hit in the game was his walk-off, two-run shot in the ninth.

Mosley, who plays the game under the handle "kamea" (his daughter's name), didn't make any picks Sunday, so his streak is intact and the big prize is in sight this week. You can track his progress here.

This is good opportunity to point out that the league batting average this season is .248, which, if it holds, would be the game's lowest since 1972, the year before the DH was added to the AL. So the odds have been significantly stacked against Mosley. Perhaps the most amazing part is that he kept his streak intact three times between Opening Day and May 3 on days he selected a Kansas City Royal (he went with Lorenzo Cain on April 13, April 20 and May 3), despite the fact that the Royals hit .214 as a club in that stretch. Mosley's picks have gone a combined 76-for-208 (.365).

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Anthony Castrovince is a Sports on Earth contributor, MLB.com columnist and MLB Network contributor. Follow him on Twitter @Castrovince.