Here's this week's college softball power rankings:
1. Oklahoma (37-2, 6-0 Big 12)
One more reason Oklahoma remains the prohibitive favorite to win it all? Keilani Ricketts has the third-best slugging percentage on the team. That's Ricketts, the reigning national player of the year who finished 19th in the country in slugging a season ago and still ranks solidly in the top 50 in that category this season. Sophomore Lauren Chamberlain remains the best run producer in college softball, but the big addition, as expected, is Shelby Pendley. The Arizona transfer hit three home runs against Texas Tech this past weekend and owns a 1.355 OPS. Now it's on to Texas for the biggest series of the season.
2. Oregon (36-6, 13-2 Pac-12)
Oregon makes the big leap this week, and it has little to do with teams that were ahead of it slipping. It's just that the team leading the Pac-12 race is starting to take on the look of a juggernaut with pitching, hitting and even passable defense. Granted, Arizona is in the midst of a free fall at the moment, but Oregon didn't break a sweat in sweeping three games against the traditional conference and national power. That included back-to-back, run-rule no-hitters in the final two games, the last a perfect game. Tuesday's doubleheader against Portland State will make it 14 games in 20 days, but then Oregon is off until visiting UCLA on April 26.
3. Arizona State (38-5, 9-3 Pac-12)
Playing without All-American Alix Johnson for the second week in a row as a result of a suspension, Arizona State lost the opener against Washington but rallied for back-to-back wins to clinch the series. Dallas Escobedo didn't start the opener but picked up both wins and allowed just two runs in 14 2/3 innings. She entered the series with a 3.82 ERA in Pac-12 games. As expected, the RPI numbers got a boost from conference play. Outside the top eight in adjusted RPI a week ago, Arizona State is sixth this week, where it needs to be to assure itself a home super regional.
4. Tennessee (38-6, 12-3 SEC)
Tennessee last lost a game on March 17. It last lost a game in regulation on March 10. So it's only Oregon's surge that costs the SEC team a spot from a week ago. All the more impressive about the 15-game winning streak is the Lady Vols have scored at least five runs in every game, including the past weekend's sweep of Auburn. The only bad news is Tennessee is still just eighth in adjusted RPI this week, with the weakest part of its conference schedule to come as it tries to lock down postseason games in Knoxville.
5. Texas (38-4, 8-0 Big 12)
No, even a series win against Oklahoma this weekend won't remove all doubt about a team with more than its share of disappointing postseasons, but it wouldn't hurt. The matchup between Blaire Luna and Ricketts is the obvious headliner when the Longhorns and Sooners meet, but it's also a chance for Taylor Hoagland to go head-to-head with all of Oklahoma's sluggers. The national leader in on-base percentage (.654), Hoagland is trying to join Sam Fischer, Megan Langenfeld, Adrienne Monka and Jen Yee as recent players to post a .650 OBP or higher for an entire season.
6. Florida (41-5, 14-4 SEC)
Cause for concern or no big deal? Only Tennessee has a better ERA than Florida among SEC teams this season, but the Gators have allowed 3.2 runs per game over their past nine. That compares to 1.7 runs per game over their first 37 games. Florida is also 7-2 in those games, including a series win on the road against a very good Kentucky team this past weekend. A midweek trip to Florida State precedes a three-game set against a good Longwood lineup.
7. Alabama (37-6, 10-5 SEC)
The Crimson Tide got three days off this past weekend (it could have been four, but their play in an 8-5 win against Mississippi Valley State last week didn't quite meet coach Patrick Murphy's standards). After a midweek game against Southern Miss, they play three series with some emotional import -- first against former assistant coach Vann Stuedeman and Mississippi State, then Murphy's first visit to LSU since he reversed course in accepting that job, and finally home against Kentucky for the first time since a devastating tornado hit Tuscaloosa and canceled the 2011 series.
8. Michigan (35-7, 12-0 Big Ten)
The only thing Michigan didn't do in a three-game series against Michigan State was play seven innings. After starting with two run-rule wins, including a 21-2 rout in the opener, the Wolverines needed extra innings to clinch the sweep (and needed a three-run rally in the seventh inning to force extra frames). That drama aside, there is little reason to expect the Wolverines to repeat their April slide of a season ago, when they lost back-to-back Big Ten series.
9. Louisville (37-6, 10-1 Big East)
With apologies to some of the teams involved, this is the portion of the schedule Louisville just needs to get through, rather than anything that is going to help it get ready for the postseason. The Cardinals, who swept three games against Connecticut (it helped that basketball star Breanna Stewart wasn't involved), next play a midweek doubleheader against Pittsburgh and then visit Villanova for three games this weekend. All three teams are outside the RPI top 100.
10. LSU (35-9, 11-4 SEC)
LSU's .391 slugging percentage and 31 extra-base hits through 15 conference games might not jump off the page, but you know what really doesn't jump off the page? A .264 slugging percentage and 25 extra-base hits in 28 conference games. That was LSU's production a season ago, and the reason its run to the World Series was such a surprise. That improved offense carried the team to two road wins at Texas A&M, including a 9-6 win in the middle game in which LSU squandered a four-run lead in the seventh inning but came up with even more in extra innings.