Welcome back to The Rotation! Here's a starting five of topics worth bantering about in Major League Baseball this week.

1. Western powers

A three-headed monster has emerged in the National League West, as the Rockies, Dodgers and D-backs could be frontrunners for three of the league's five postseason spots. All of those clubs are on pace for at least 102 wins, and entering the week, FanGraphs was giving each at least an 81.2 percent chance of reaching the postseason.

Now, some of that percentage is due to the dynamics of an NL East in which the Nationals are miles ahead of the pack and an NL Central that's struggling. And having two other intradivision rivals with winning percentages of .400 or less (the Dodgers, Rox and D-backs are a combined 37-19 vs. the Padres and Giants) doesn't hurt, either.

But no doubt, something special is going on at the top of the NL West.

"We've still got to go out and play," Dodgers manager Dave Roberts told reporters, "but it's clearly the best division in baseball. It's going to be a fun September."

Part of the fun revolves around impact from previously unproven assets.

No one could have imagined how much of an impact rookie Cody Bellinger would have on L.A. Bellinger "failed" to go deep Sunday, so he'll have to settle for tying Gary Sanchez for the most home runs (19) in the first 50 games of a career, and he's on pace to break the NL rookie homer record (38, Frank Robinson and Wally Berger) and fall just shy of Mark McGwire's overall record (49 in 1987).

The Rockies' rotation, with would-be ace Jon Gray on the shelf, has been led by four rookies, with Kyle Freeland, Antonio Senzatela, German Marquez and Jeff Hoffman posting a collective ERA of 3.66 (not bad for a group that calls Coors Field home).

Meanwhile, in Arizona, the most impactful "rookie" is D-backs skipper Torey Lovullo, whose Joe Maddon-like clubhouse qualities have improved the club's atmosphere. But how about the surprise standing of 25-year-old Robbie Ray (2.87 ERA, .197 average against) among the NL's top starting arms this season? Ray was a piece of two pretty big trades (Doug Fister to the Nats in 2013 and Didi Gregorius to the Yankees in a three-team deal in 2014) and is just now living up to his prospect potential.

We've got consecutive series this week featuring the West's best -- D-backs at Rockies on Tuesday through Thursday, then Rockies at Dodgers next weekend. These aren't just battles for divisional supremacy but, quite likely, for October seeding.

2. Edwinning

The AL Central standings look a lot more like we expected following the Indians' four-game takeover of the Twin Cities over the weekend. The defending AL champs went from two back to two up in the Central, and while there are many elements involved in such a clean sweep, Edwin Encarnacion's continued recovery from a characteristically slow start to the season is the most exciting element of all.

No free-agent position player who changed teams over the winter got more money than Encarnacion did with his surprise three-year, $60 million deal, so that .199 average he was sitting on at the end of play on May 27 wasn't going over well with the Cleveland faithful. Encarnacion had more swings-and-misses inside the zone than ever before in his career, so it was fair to wonder if the bat speed had slowed, even if the thought of it going away overnight seemed extreme.

Since then, though, Encarnacion's batting .369 with nine homers, including an upper-deck shot on Sunday.

The recent uptick has been dramatic enough that Encarnacion's full-season weighted runs created plus mark (132) is now pretty much identical to last year's number in Toronto (134).

This return to normalcy for the Tribe's signature slugger has made the NL Central race even more intriguing. The Tribe and Twins will meet up again next weekend in Cleveland to see if these current standings will stabilize.

3. The Cole truth

We don't know if the Pirates will actually entertain trade offers for Gerrit Cole this summer. If they do, the Bucs would have the potential to command the biggest trade package in this summer market, because a 26-year-old arm just two years removed from NL Cy Young Award contention and under arbitration control through 2019 is precisely what contending clubs like the Astros and Cubs would have at the top of their priority list.

While a resurgent Andrew McCutchen (1.201 OPS dating back to May 26) could be a trade candidate for a Pirates team seven games under .500 and six back in a weak division, Cole has greater value on account of his age, position and profile. The problem is that Cole hasn't done his profile many favors in this 2017 season in which his adjusted ERA+ is just below league average (96). He recently had a four-start stretch in which he gave up 23 earned runs on 39 hits with eight homers in 19 1/3 innings.

But market value is very often oriented around small, recent samples, and Cole's seven innings of one-run ball against a tough Rockies lineup last week was a big step forward. His next assignment comes Monday night in Milwaukee, and evaluators are watching each of Cole's starts closely to see if it's worth offering Pittsburgh the moon and the stars for their young ace. Whether they would actually bite is another matter altogether, but it bears repeating that if Cole can straighten himself out between now and July 31, he has the potential to remake this market.

4. Hamels time?

In other "pitchers named Cole" news, Cole Hamels is due to make his second rehab start Wednesday as he makes his return from a strained oblique muscle. The Rangers are talking about possibly returning Hamels to the big-league rotation as soon as one week from now.

This is an interesting and important development in the AL Wild Card picture, because the Rangers are one of those clubs clearly teetering on the buy/sell line six weeks ahead of the Trade Deadline. Texas took two of three from the rival Astros last week, but they're still basically Texas Toast in the AL West, and it remains to be seen if president of baseball operations Jon Daniels would value a potential Wild Card run enough to ignore the system-stocking possibility of a Yu Darvish deal.

A healthy Hamels, joining a rotation that also now features a healthy Tyson Ross (who was solid in his season debut against the Mariners over the weekend), could help make a convincing case for going for it. The Rangers have, after all, won seven of their last nine, and their offense is finally healthy and hitting, averaging 5.7 runs per game in that span. The Rangers were six games under .500 on May 3, when Hamels hit the DL. Things looked awfully bleak then, but they're not out of the AL playoff picture yet. 

5. In the Rizzone

"It's crazy, it's weird, it's funny, but it's great."

That's a sentence that could be used by many people to describe many things (my wife on living with me, for instance), but that's how Anthony Rizzo described his turn in the Cubs' leadoff spot the last week. Since Maddon made that move last Tuesday, Rizzo has gone 4-for-4 with two homers, a double and a walk when leading off games. The Cubs as a whole have scored 37 runs in the five games, winning three of them (which, by the standards of the 2017 Cubs, is major momentum).

It can be easy to pooh-pooh lineup construction. Studies have found it to be largely immaterial. Stack your best hitters near the top and, on measure, you'll look like pretty smart. Rizzo has seen a slight uptick in percentage of pitches in the strike zone since he made the move, and that's helped contribute not just to his leadoff success, but to his 12-game hitting streak.

But you can't discount the fun factor in the long grind of 162, and Maddon's move has, as evidenced by Rizzo's tongue-in-cheek boast that he's the "greatest leadoff hitter of all-time," brought out Rizzo's silly-and-self-confident side -- the same kind of vibe that inspired his pre-Game 7 naked "Rocky" speech during last year's World Series. That can only be a good thing for a Cubs club trying to find its footing.

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